Price  One  Shilling. 


cosmos: 


A    SURVEY 


GENERAL  PHYSICAL  HISTORY 


OF 


THE  UNIVERSE. 


BY 

ALEXANDER  VON  HUMBOLDT. 


NEW-YORK: 

HARPER  &  BROTHERS,  PUBLISHERS, 

82  CLIFF  STREET. 

1845. 


oil 
MORSE'S  NEW  PICTORIAL  GEOGRAPHY. 

PRICE  FIFTY  CENTS. 

EMBELLISHED  BY  NEARLY  ONE  HUNDRED  AND  FIFTY  ENGRATOGS IND  ABOUT  FIFTY  MAPS. 
EXECUTED  IN  THE  NEW  CEROGRAPHIC  PROCESS. 


No  equivocal  evidence  of  the  great  merits  ef  this  popular  New  School  Geography"  is  afford- 
ed by  the  fact  that  nearly  one  hundred  thousand  copies  have  been  already  disposed  of  within 
the  brief  interval  of  its  publication.  It  wUl  be  found  one  of  the  most  beautiful  in  its  pictorial 
embellishments,  lucid  and  simple  in  its  adaptation  to  the  purposes  of  instruction,  as  well  as 
one  of  the  cheapest  of  all  works  of  the  kind  ever  produced.  The  maps  are  both  novel  and 
attractive,  being  over  fifty  in  number,  printed  in  colours  by  the  new  cerographic  process. 


TESTIMONIALS  FROM  THE  PHILADELPHIA  PUBLIC  SCHOOLS. 


The  best  work  on  Geography  in  the  United  States  or 
Great  Britain:  it  should  find  its  way  into  the  Common 
Schools  and  all  seminaries  of  learning  in  the  TJ.  States. 
Its  admirable  arrangement  and  portability  render  it  an  ex- 
cellent work  of  referenec  ;  no  person  should  be  without  it. 

Amdbew  Cbozier,  Principal  of  Reed  St.  Gram.  School. 

ATaluable  acquisition  to  all  engaged  either  in  imparting, 
or  receiving  instruction.  Its  conciseness  and  simplicity  of 
arrangement,  and  its  numerous  and  beautiful  embellish- 
ments, eannot  fail  to  render  it  deservedly  popular. 

W.  H.  Pile,  Principal  qf  N.  E.  Gram.  School. 


I  kave  examined  with  some  eare  the  "  Getgraphy^'  by 
Morse,  and  can  say  that  I  am  particularly  pleased  with  it. 
I  tlunk  it  clear  and  concise  in  its  views,  and  that  the  maps 
and  letter-press  being  in  juxtaposition,  is  a  recommendation 
Bot  likely  to  be  passed  by  in  silence.  This  arrangement  is 
calculated  to  facilitate  the  progress  of  the  learner,  inasmuch 
as  he  has  not  te  look  to  a  separate  book  for  his  map  :  thus 
time  is  gained,  and  more  ground  gone  over  in  the  same  pe- 
nod.  I  would  therefwe  cheerfully  recommend  it  to  all  who 
ftre  in  want  of  such  a  work. 

W.  Q.  E.  Aqnbw,  Printipdl  of  Zane  St.  Pub.  McJiool. 


We  Gomeur  in  the  opinion  with  Mr.  Agnew. 

,  James  Rhoads,  Principal  of  N.  W.  Gram.  School. 
A.  T.  W.  Wbight,  Principal  of  Model  School. 


I  decidedly  approve  of  it ;  the  facility  afforded  the  pupil 
In  rrferring  to  the  maps,  the  correctness  of  the  political  di- 
visions, and  of  the  population  of  towns  ;  the  eonciseness  of 
style  and  description,  and  the  cheapness,  as  well  as  the 
neatness  and  beauty  of  the  typographical  exeeution  of  the 
werk  are,  in  my  opinion,  strong  recommendations  to  the 
public.         W.  W.  WooB,  Prine^td  •f  S.  W.  Gram.  Seh. 

It  i«  Ike  beat  work  on  ibe  subject  with  whioK  I  am  ao- 
qaainted.    It  has  several  advantages  orer  other  works  of 


the  kind ;  one  is,  that  the  map,  questions  on  the  map,  and 
description  of  each  country,  are  on  the  same  page. 
S.  F.  Watson,  Principal  of  Catherine  St.  Gram,  School. 

I  cheerfully  concur  in  the  above  recommendation. 
B.  E.  Chambeblin ,  Prin.  of  Buttontoood  St.  Gram.  Seh, 

Novelty  does  not  necessarily  imply  improTement,  but  in 
this  instance  we  have  an  improvement  by  which  the  efforts 
of  the  young  pupil  will  be  very  much  assisted  in  the  acqui 
sition  of  geographical  knowledge. 

M.  S.  Cleavenqer,  )  Principals  of  Locust  St. 

E.  H.  Cox,  J      Gram.  School. 


I  have  examined  the  work,  and  think  it  well  adapted  to 
the  use  of  schools.  Apart  from  the  consideration  that  its 
descriptions  are  written  in  a  concise,  yet  perspicuous  style, 
the  convenient  general  arrangement  of  the  work  and  its  nu- 
merons  illustrations  render  it  superior  to  any  system  of  Ge- 
ography now  in  use. 

L.  e.  Smith,  Prin.  ofJT.  Ladies  Cram.  School,  Zone  St. 

It  afR>rd8  me  pleasure  to  recommend  it  to  teachers  aa4 
the  public  in  general.  The  arrangement  is  well  planned, 
and  affords  many  facilities  to  the  study  of  geography  that 
were  much  desired.  The  maps  are  certainly  much  superior 
to  any  thing  of  the  kind  that  has  yet  appeared. 

L.  Hopper,  Principal  qf  Third  Bt.  School. 


I  have  no  hesitation  in  assigning  to  it  the  first  rank  among 
similar  books  now  in  use  ;  its  excellent  maps,  and  beautiful 
pictorial  illustrations,  are  calculated  to  arrest  the  attention 
of  the  pupil,  and  impress  instruction  indelibly  on  his  mem- 
ory.      Wm.  Roberts,  Prin.  of  Moyamensing  Gram.  Seh. 

Having  examined  "  Morsels  School  Geographyy"  wc  thiiA 

it  admirably  calculated  to  carry  out  the  views  of  its  author 

P.  A.  CRKaoB,  Principal  of  S.  E.  Gram.  Sohod 

S.  D.  JOHMSTOIT. 
L.  N.  BOSWELL. 


(*^ 


HARPER  &  BROTHERS,  PUBLISHERS,  NEW-YORK. 

ANB  MAY  BK   OBTAIHKD    OP   THK   B08K8BLI.BR8   THROUOHOUT   TIW    VWmV    STAraa. 


TO  THE  READER. 


In  presenting  the  English  public  with  a  version,  in  the  vernacular  tongue, 
of  the  world-renow^ned  Alexander  von  Humboldt's  Cosmos,  the  Translator 
begs  to  say,  that  he  has  striven  to  give  a  faithful  transcript  of  the  original,  not 
less  in  matter  than  in  manner :  he  has  not  taken  away  from  the  work,  he  has 
not  added  to  it ;  and  he  has  farther  done  what  in  him  lay  to  preserve  the  lofty 
tone  and  imaginative  style  of  the  Author. 

The  Introduction  is  composed  in  the  manner  of  an  oration  or  popular  dis- 
course, and  scarcely  admitted  of  so  literal  a  transfusion  into  English  as  the 
Translator  will  feel  it  his  duty  to  secure  in  the  body  of  the  work.  The  sec- 
ond section,  on  the  Limitation  and  Scientific  Treatment  of  Physical  Cosmog- 
raphy, is  extremely  abstruse,  and  cost  the  Translator  no  small  pains  to  ren- 
der it,  he  trusts  intelligibly,  into  English.  With  the  third  section— The  Pic- 
ture of  Nature,  dtc. — the  Author  enters  fairly  on  his  task. 

For  the  use  of  several  compound  words,  formed  after  the  German  origi- 
nals, the  Translator  has  to  apologize  to  the  classical  English  reader,  and  for 
mistakes  that  may  occur  in  the  translation  of  technical  or  conventional  scien- 
tific terms,  he  must  meantime  crave  the  indulgence  of  the  deeply  versed  in  the 
several  disciplines  where  these  occur.  He  can  but  refer  to  the  singular  dif- 
ficulties of  his  task,  and  solicit  indulgence* 

June  28lA,  1845. 


Digitized  by  tine  Internet  Archive 

in  2008  with  funding  from 

IVIicrosoft  .Corporation 


http://www.archive.org/details/cosniossurveyofgeOOhumbrich 


COSMOS: 
SKETCH  OF  A  PHYSICAL  HISTORY  OF  THE  UNIVERSE. 


INTRODUCTION. 

THE  VARIOUS  SOURCES  OF  OUR  ENJOYMENT  IN  THE 

CONTEMPLATION    OF    NATURE. THE    SCIENTIFIC 

FOUNDATION    OF  THE   LAWS    THAT   GOVERN  THE 
UNIVERSE.* 

In  undertaking  thus,  after  so  long  an  absence 
from  my  native  country,  to  discourse  with  you 
freely  on  the  general  physical  phenomena  of 
our  globe,  and  to  develop  the  connection  of 
the  forces  which  actuate  the  universe,  I  feel 
myself  oppressed  with  a  two-fold  difficulty. 
On  one  hand,  the  subject  I  have  to  treat  is  so 
vast,  and  the  time  allowed  me  is  so  short,  that 
I  am  fearful  either  of  appearing  superficial,  or 
else,  generalizing  over  much,  of  proving  tire- 
some to  you  through  aphoristic  brevity.  On 
the  other,  the  life  of  action  I  have  led  has  pre- 
pared me  indifferently  for  the  duty  of  a  public 
teacher ;  so  that,  in  the  embarrassed  state  of 
my  mind,  I  fear  I  may  not  always  succeed  in 
expressing  myself  with  the  clearness  and  pre- 
cision which  the  vastness  and  the  variety  of 
my  subject  require.  But  the  realm  of  nature 
is  also  the  realm  of  freedom ;  and  to  exhibit  in 
lively  characters  the  ideas  and  emotions  which 
a  true  love  of  nature  inspires,  the  language 
must  likewise  move  in  harmony  with  the  dig- 
nity and  freedom  of  the  subject,  and  this  it  is 
only  given  to  high  mastery  to  impart. 

He  who  regards  the  influences  of  the  study 
of  nature  in  their  relations  not  to  particular 
grades  of  civilization  or  the  individual  require- 
ments of  social  life,  but  in  their  wider  bearings 
upon  mankind  at  large,  promises  himself,  as 
the  principal  fruit  of  his  researches,  that  the 
enjoyment  of  nature  will  be  increased  and  en- 
nobled through  insight  into  the  connection  of 
her  phenomena.  Such  increase,  such  nobility, 
however,  is  the  work  of  observation,  of  intelli- 
gence, and  of  time,  in  which  all  the  efforts  of 
the  understanding  of  man  are  reflected.  How 
the  human  kind  have  been  striving  for  thou- 
sands of  years,  amidst  eternally  recurring  chan- 
ges in  the  forms  of  things,  to  discover  that 
which  is  stable  in  the  law,  and  so  gradually, 
by  the  might  of  mind,  to  vanquish  all  within 
the  wide-spread  orbit  of  the  earth,  is  familiar 
to  him  who  has  traced  the  trunk  of  our  knowl- 
edge through  the  thick  strata  of  bygone  ages  to 
its  root.  To  question  these  ages  is  to  trace  the 
mysterious  course  of  the  idea  stamped  with  the 
same  image  as  that  which,  in  times  of  remote 
antiquity,  presented  itself  to  the  inward  sense 
in  the  guise  of  an  harmoniously  ordered  whole. 
Cosmos,  and  which  meets  us  at  last  as  the  prize 
of  long  and  carefully  accumulated  experience. 

*  A  Discourse  delivered  on  opening  the  Course  of  Lec- 
tures in  the  Great  Hall  of  the  Singing  Academy  of  Berlin. 
Many  interpolations  belong  to  a  later  period. 


In  these  two  epochs  in  the  contemplation 
of  creation — the  first  dawn  of  consciousness 
among  men,  and  the  ultimate  and  simultaneous 
evolution  of  every  element  of  human  science — 
two  distinct  kinds  of  enjoyment  are  reflected. 
The  mere  presence  of  unbounded  nature,  and 
an  obscure  feeling  of  the  harmony  that  reigns 
amidst  the  ceaseless  changes  of  her  silent  work- 
ings, are  the  source  of  the  one.  The  other  be- 
longs to  a  higher  stage  of  civilization  of  the  spe- 
cies, and  the  reflection  of  this  upon  the  individ- 
ual ;  it  springs  from  an  insight  into  the  order 
of  the  universe,  and  the  co-ordination  of  the 
physical  forces.  Even  as  man  now  contrives 
instruments  by  which  he  may  question  nature 
more  closely,  and  steps  beyond  the  limited  cir- 
cle of  his  fleeting  existence  ;  as  he  no  longer 
observes  only,  but  has  learned  to  produce  phe- 
nomena under  determinate  conditions  ;  as,  in 
fine,  the  philosophy  of  nature  has  doffed  hei 
ancient  poetical  garb,  and  assumed  the  earnest 
character  of  a  thinking  impersonation  of  things 
observed,  positive  knowledge  and  definition 
have  taken  the  place  of  obscure  imaginings  and 
imperfect  inductions.  The  dogmatical  specu- 
lations of  former  ages  only  exist  at  present  in 
the  prejudices  of  the  vulgar,  or  in  circumstan 
ces  where,  as  if  conscious  of  their  weakness, 
they  willingly  keep  themselves  in  the  shade. 
They  also  maintain  themselves  as  a  heavy  in- 
heritance in  language,  which  is  disfigured  by 
symbolical  words  and  phrases  innumerable.  A. 
small  number  only  of  the  elegant  creations  of 
the  imagination  which  have  reached  us,  sur- 
rounded as  it  were  with  the  haze  of  antiquity, 
acquire  a  more  definite  outline  and  a  renovated 
shape.  I 

Nature,  to  the  eye  of  the  reflecting  observer, 
is  unity  in  multiplicity ;  it  is  combination  of 
the  manifold  in  form  and  composition ;  it  is 
the  conception  of  natural  things  and  natural 
forces  as  a  living  whole.  The  most  important 
consequences  of  physical  researches  are  there- 
fore these  :  To  acknowledge  unity  in  multipli- 
city ;  from  the  individual  to  embrace  all ;  amidst 
the  discoveries  of  later  ages  to  prove  and  sep- 
arate the  individuals,  yet  not  to  be  overwhelmed 
with  their  mass  ;  to  keep  the  high  destinies  of 
man  continually  in  view  ;  and  to  comprehend 
the  spirit  of  nature  which  lies  hid  beneath  the 
covering  of  phenomena.  In  this  way  our  aspi- 
rations extend  beyond  the  narrow  confines  of 
the  world  of  sense,  and  we  may  yet  succeed, 
comprehending  nature  intimately,  in  master- 
ing the  crude  matter  of  empirical  observation 
through  the  might  of  mind. 

When,  in  the  first  place,  we  reflect  on  the 
different  degrees  of  enjoyment  which  the  con- 
templation of  nature  affords,  we  find  that  the 
first  or  lowest  are  independent  of  all  insight 


INTRODUCTION. 


into  the  operation  of  her  forces,  yea,  almost  of 
the  special  character  of  the  objects  that  are 
surveyed.     "When,  for  instance,  the  eye  rests 
Upon  the  surface  of  some  mighty  plain,  covered 
with  a  monotonous  vegetation,  or  loses  itself 
in  the  horizon  of  a  boundless  ocean,  whose 
waves  are  rippling  softly  to  the  shore,  and 
strewing  the  beach  with  sea-weed,  the  feeling 
of  free  nature  penetrates  the  mind,  and  an  ob- 
scure intimation  of  her  "endurance  in  con- 
formity with  inherent  everlasting  laws,"  takes 
possession  of  the  soul.     In  such  emotions  there 
dwells  a  mysterious  power ;  they  are  exciting, 
yet  composing  ;  they  strengthen  and  quicken 
the  jaded  intellect ;  they  soothe  the  spirit,  pain- 
fully commoved  by  the  wild  impulses  of  pas- 
sion.   All  of  earnest  and  of  solemn  that  dwells 
with  us,  is  derived  from  the  almost  unconscious 
sentiment  of  the  exalted  order  and  sublime  reg- 
ularity of  nature ;  from  the  perception  of  unity 
of  plan  amidst  eternally  recurring  variety  of 
form — for  in  the  most  exceptional  forms  of  or- 
ganization, the  General  is  still  faithfully  reflect- 
ed ;  and  from  the  contrast  betwixt  the  sensu- 
ous infinite  and  the  particular  finite,  from  which 
we  seek  to  escape.    In  every  climate  of  the 
globe,  wherever  the  varying  forms  of  animal 
and  vegetable  life  present  themselves,  in  every 
grade  of  intellectual  eminence  are  these  benef- 
icent influences  vouchsafed  to  man. 

Another  kind  of  enjoyment  of  nature,  which 
is  likewise  wholly  and  solely  addressed  to  the 
feelings,  is  that  which  we  experience,  not  from 
the  simple  presence  of  unbounded  nature,  but 
from  the  individual  characters  of  a  country,  and 
for  which  we  have  to  thank  the  peculiar  physi- 
ognomical attributes  of  the  surface  of  our  plan- 
"*     Impressions  of  this  kind  are  more  lively, 


et 


the  vine-clad  hills  of  Orotava,  and  the  Hesperi- 
dian  gardens  that  line  the  shore.  In  scenes  like 
these,  it  is  no  longer  the  still  creative  life  of 
Nature,  her  peaceful  strivings  and  doings,  that 
address  us  ;  it  is  the  individual  character  of  the 
landscape,  a  combination  of  the  outlines  of 
cloud  and  sky,  and  sea  and  coast,  sleeping  in 
the  morning  or  the  evening  light  ;  it  is  the 
beauty  of  the  forms  of  the  vegetable  world,  and 
their  groupings,  that  appeal  to  us  ;  for  the  im- 
measurable, and  even  the  awful  in  nature — all 
that  surpasses  our  powers  of  comprehension — 
becomes  a  source  of  enjoyment  in  a  romantic 
country.  Fancy  brings  into  play  her  creative 
powers  upon  all  that  cannot  be  fully  attained 
by  the  senses,  and  her  workings  take  a  new 
direction  with  each  varying  emotion  in  the  mind 
of  the  observer.  Deceived,  we  imagine  that 
we  receive  from  the  external  world  what  we 
ourselves  bestow. 

When,  after  a  lengthened  voyage,  and  far  from 
home,  we  for  the  first  time  set  foot  in  a  tropical 
land,  we  are  pleased  to  recognize  in  the  rocks 
and  mountain  masses,  the  same  mineral  spe- 
cies we  have  left  behind — clay  slate,  basaltic 
amygdaloid,  and  the  like,  the  universal  distri- 
bution of  which  seems  to  assure  us,  that  the 
old  crust  of  the  earth  has  been  formed  inde- 
pendently of  the  external  influences  of  exist- 
ing climates.  But  this  well-known  crust  is 
covered  with  the  forms  of  a  foreign  flora.  Yet 
here,  surrounded  by  unwonted  vegetable  forms, 
impressed  with  a  sense  of  the  overwhelming 
amount  of  the  tropical  organizing  force,  in  pres- 
ence of  an  exotic  nature  in  all  things,  the  na- 
tive of  the  northern  hemisphere  has  revealed 
to  him  the  wonderful  power  of  adaptation  in- 
herent in  the  human  mind.    We  feel  ourselves. 


more  definite,  and  therefore  especially  adapted   in  fact,  akin  to  all  that  is  organized  ;  and  though 


to  particular  moods  of  the  mind.  Here,  it  is 
the  magnitude  of  the  masses,  exposed  amidst 
some  wild  conflict  of  the  elements,  that  arrests 
us  ;  there,  it  is  a  picture  of  the  immoveably 
fxed  that  meets  the  eye,  as  in  the  waste  and 
stillness  of  the  boundless  prairies  of  the  New 
World  and  of  the  steppes  of  Northern  Asia ;  or 
it  is  a  softer  and  more  hospitable  view  that  at- 
tracts us— a  cultivated  country,  or  the  first 
hermitages  of  man  amidst  the  wilderness,  sur- 
rounded by  craggy  peaks,  on  the  margin  of  the 
leapmg  brook.  For  it  is  not  so  much  the 
strength  of  the  emotion  that  indicates  the  de- 
gree of  the  particular  enjoyment  of  nature,  as 
the  determinate  circle  of  ideas  and  feelings 
which  induce  and  give  it  endurance. 

If  I  might  here,  for  a  moment,  yield  to  my 
own  recollections  of  grand  natural  scenery,  I 
would  revert  to  the  ocean,  under  the  softness 
of  a  tropical  night,  with  the  vault  of  heaven 
pouring  down  its  planetary  and  steady,  not 
twinkling,  starlight  upon  the  heaving  surface 
of  the  world  of  waters ;  or  I  would  call  to  mind 
the  wooded  valleys  of  the  Cordilleras,  where, 
instinct  with  power,  the  lofty  palm-trees  break 
through  the  dark  canopy  of  foliage  below,  and 
rising  like  columns,  support  another  wood 
above  the  woods(*) ;"  or,  I  transport  myself  to 
the  Peake  of  Teneriffe,  and  see  the  cone  cut 
off  from  the  earth  beneath  by  a  dense  mass  of 
clouds,  suddenly  becoming  visible  through  an 
opening  pierced  by  an  upward  current  of  air, 
and  the  edge  of  the  crater  looking  down  upon 


at  first  we  may  fancy  that  one  of  our  native 
landscapes,  with  its  appropriate  features,  like 
a  native  dialect,  would  present  itself  to  us  in 
more  attractive  colours,  and  rejoice  us  more 
than  the  foreign  scene  with  its  profusion  of 
vegetable  life,  we  nevertheless  soon  begin  to 
find  that  we  are  burghers,  even  under  the  shade 
of  the  palms  of  the  torrid  zone.  In  virtue  of 
the  mysterious  connection  of  all  organic  forms 
(and  unconsciously  the  feeling  of  the  necessity 
of  this  connection  lies  within  us),  these  new 
exotic  forms  present  themselves  to  our  fancy 
as  exalted  and  ennobled  out  of  those  which 
surrounded  our  childhood.  Blind  feeling,  there- 
fore, and  the  enchainment  of  the  phenomena 
perceived  by  sense,  in  the  same  measure  as 
reason  and  the  combining  faculty,  lead  us  to  the 
recognition  which  now  penetrates  every  grade 
of  humanity,  that  a  common  bond,  according 
to  determinate  laws,  and  therefore  eternal,  em- 
braces the  whole  of  animated  nature. 

It  is  a  bold  undertaking  to  subject  the  magic 
of  the  world  of  sense  to  dissection,  to  a  separa- 
tion of  its  elements  ;  for  the  character  of  gran- 
deur in  a  landscape  is  especially  determined  by 
this,  that  the  most  impressive  natural  phenom- 
ena present  themselves  at  once  and  together 
to  the  mind — that  a  host  of  ideas  and  feelings 
are  simultaneously  excited.  The  extent  of 
mastery  over  the  feelings  which  is  thus  gained, 
is  most  intimately  connected  with  the  unity  of 
the  impression.  But  if  we  would  explain  the 
power  of  the  entire  impression  by  the  diversity 


INTRODUCTION. 


of  the  phenomena,  we  must  descend  into  the 
realm  of  determinate  natural  forms  and  active 
forces,  and  there  discriminate  and  distinguish. 
The  widest  and  most  varied  scope  for  investi- 
gations of  this  kind  is  afforded  by  the  land- 
scapes of  Southern  Asia  and  of  the  New  World  ; 
countries  where  stupendous  mountain  masses 
form  the  bottom  and  boundary  of  the  atmo- 
spheric ocean,  and  where  the  same  volcanic 
powers  which  once  forced  up  the  mighty  ram- 
part of  the  Andes,  through  vast  chasms  in  the 
earth,  sill  continue  to  shake  their  work  to  the 
terror  of  its  inhabitants. 

But  natural  pictures,  arranged  in  succession 
and  in  harmony  with  some  leading  idea,  are  not 
calculated  merely  to  engage  the  attention  agree- 
ably ;  in  their  sequence  they  may  farther  be 
made  to  compose  a  kind  of  scale  of  natural  im- 
pressions, which,  in  their  gradually  increasing 
intensity,  may  be  followed  from  the  waste  with- 
out a  blade  of  grass,  to  the  luxuriant  vegetation 
of  the  torrid  zone ;  ffom  the  monotonous  level, 
to  the  grandest  mountain  chains.  Were  we, 
giving  the  rein  to  fancy,  to  suppose  Mount  Pi- 
latus  piled  upon  Shreekhorn,(")  or  Schnee- 
koppe  set  upon  Mont  Blanc,  we  should  still  fall 
short  of  one  of  the  higher  peaks  of  the  Andes, 
Chimborazo,  which  has  twice  the  height  of 
Etna ;  and  were  we  to  throne  the  Rigi,  on 
Mount  Athos,  on  Chimborazo,  we  should  only 
have  an  image  of  the  highest  summit  of  the 
Himalaya,  Dhawalagiri.  Although  the  Indian 
mountains,  therefore,  far  exceed  the  Andes  in 
colossal  massiness,  a  fact  now  made  certain  by 
repeated  measurements,  they  still  present  no- 
thing like  the  variety  of  feature  which  charac- 
terises the  Cordilleras  of  South  America.  It  is 
not  elevation  alone  that  gives  Nature  her  pow- 
er of  impressing  the  mind.  The  Himalaya 
range  lies  far  beyond  the  limits  of  tropical  cli- 
mates ;  scarcely  do  we  find  a  palm-tree  stray- 
ing into  the  beautiful  valleys  of  Nepaul  and  Ku- 
inaon.(^)  Between  the  28th  and  34th  parallels 
of  latitude,  in  the  dependencies  of  the  ancient 
Paropamisus,  the  vegetable  kingdom  no  longer 
displays  the  same  luxuriance  of  arborescent 
ferns  and  grasses,  or  of  large-flowered  orchid- 
eous  plants  and  bananas,  as  she  does  within 
the  tropics,  even  to  plateaus  some  thousands 
of  feet  above  the  level  of  the  sea.  Under  the 
shadows  of  the  cedar-like  deodwara  pines  and 
large-leaved  oaks,  the  vegetable  forms  of  Eu- 
rope and  the  north  of  Asia  are  found  covering 
the  granitic  rocks  that  form  the  substrata  to 
the  soil  of  the  Indian  mountains.  They  are 
not  the  same  species,  indeed,  but  they  are  sim- 
ilar forms :  junipers,  alpine  birches,  gentians, 
parnassias,  and  prickly  species  of  Ribes.(*)  The 
Himalaya,  too,  is  without  the  varying  phenom- 
ena of  active  volcanos,  which,  among  the 
islands  of  the  Indian  Ocean,  threateningly  re- 
mind us  of  the  internal  life  of  the  globe.  And 
then,  on  its  southern/ ridges  at  least,  where  the 
moister  air  of  Hindostan  deposits  its  burthen, 
the  line  of  eternal  snow  is  mostly  met  with  at 
an  elevation  of  from  eleven  to  twelve  thousand 
feet,  and  so  sets  an  earlier  limit  to  the  evolu- 
tion of  organic  life,  than  in  the  equinoctial  coun- 
tries of  South  America,  where  organization 
extends  almost  two  thousand  six  hundred  feet 
higher.(') 
Mountainous  countries  near  the  equator  have 


another  peculiarity,  not  sufficiently  regarded  : 
they  constitute  the  portion  of  the  surface  of  our 
planet,  where,  within  the  narrowest  limits,  the 
multiplicity,  or  variety,  of  natural  impressions 
attains  its  maximum.  In  the  deeply-cleft  An- 
des of  New  Granada  and  Quito,  mankind  have 
the  privilege  of  contemplating  all  the  varieties 
of  vegetable  form,  and  of  seeing  all  the  stars  in 
the  firmament  at  once.  The  same  glance  rests 
on  heliconias,  feathery  palms  of  the  loftiest 
growth,  and  bambusas  ;  over  these  character- 
istic forms  of  the  tropical  world,  are  seen  oak 
forests,  mespilus  kinds,  and  umbelliferous 
tribes,  as  in  our  European  latitudes  ;  and  turn- 
ing from  earth  to  heaven,  the  eye  takes  in  the 
southern  cross  and  Magellanic  clouds,  and  the 
northern  polar  star.  There,  the  fruitful  bosom 
of  the  earth,  and  both  hemispheres  of  the  heav- 
ens, display  at  once  the  whole  stores  of  their 
phenomena,  their  endless  variety  of  forms  and 
features ;  there  are  all  the  climates  of  the  globe, 
and  the  vegetable  zones  they  severally  deter- 
mine, superimposed  ;  there  are  the  laws  of  de- 
clining temperature,  clearly  understood  of  the 
careful  observer,  written  in  everlasting  charac- 
ters on  the  precipitous  slopes  of  the  mountains. 
I  but  lift  a  corner  of  the  veil  from  my  recollec- 
tions of  tropical  landscapes  here,  that  I  may 
not  weary  this  assembly  with  the  repetition  of 
ideas  which  I  have  endeavoured  to  represent  in 
an  illustrated  work  on  the  "  Geographical  Dis- 
tribution of  Plants(6)."  What  to  the  feelings 
melts  into  indefiniteness  and  indistinctness, 
like  misty  mountain  air,  is  only  to  be  compre- 
hended by  searching  reason,  when  viewed  in 
its  casual  connection  with  general  phenomena, 
resolved  into  its  constituent  elements,  and  as 
the  expression  of  an  individual  natural  charac- 
ter. But  in  the  circle  of  science,  as  in  the 
brilliant  circles  of  descriptive  poetry  and  land- 
scape painting,  the  representation  still  gains  in 
clearness  and  objective  animation,  as  the  Indi- 
vidual is  more  clearly  indicated  and  defined. 

If  tropical  countries  be  richer  in  means  of 
impressing  the  feelings,  through  the  variety  and 
luxuriance  of  Nature,  they  are  also  (and  the 
point  of  view  now  taken  is  the  most  important 
in  the  train  of  ideas  which  I  am  at  present 
pursuing)  especially  fitted,  in  the  uniform  reg- 
ularity of  their  meteorological  phenomena,  in 
their  succession  of  organic  developments,  and 
the  sharp  separation  of  forms  effected  by  the 
perpendicular  rise  of  the  surface,  to  present  to 
the  mind  the  order  and  harmony  of  the  heav- 
ens, mirrored,  as  it  were,  in  the  life  of  the 
globe.  Let  us  pause  for  a  moment,  and  con- 
template this  picture  of  harmonious  regularity, 
which  is  itself  connected  with  numerical  rela- 
tions. 

In  the  burning  plains  raised  but  little  above 
the  level  of  the  southern  ocean,  we  find,  in 
their  greatest  luxuriance.  Bananas,  Cycadeas, 
and  Palms ;  after  them,  shaded  by  the  lofty 
sides  of  the  valleys,  arborescent  Ferns  ;  next 
in  succession,  in  full  plenitude  of  growth,  and 
ceaselessly  bedewed  by  cool  misty  clouds,  the 
Cinchonas,  which  yield  the  far-famed  and  pre- 
cious febrifuge  barks.  Where  lofty  trees  no 
longer  grow,  we  meet  with  Aralias,  Thibaudias, 
and  myrtle-leaved  Andromedas,  associated  and 
blooming  in  company.  The  Alpine  rose  of  the 
Cordilleras,  the  Befaria,  rich  in  resinous  gum, 


INTRODUCTION. 


forms  a  purple  belt  about  the  mountains.  In 
the  stormy  region  of  the  Paramos,  all  the  more 
lofty  vegetables  and  large  flowering  herbs  grad- 
vally  disapper.  Glumaceous  monocotyledo- 
cous  tribes  now  cover  the  surface  without  vari- 
ety, and  form  unbounded  meadows,  looking  yel- 
low in  the  distance,  where  the  Llama  sheep  is 
seen  feeding  in  solitude,  and  the  cattle  intro- 
duced by  Europeans  roam  in  herds.  Upon  the 
naked  masses  of  trachytic  rock,  which  here 
and  there  rise  above  the  surface  of  the  turf-clad 
soil,  none  but  plants  of  the  lowest  organization 
can  thrive  :  the  tribe  of  liverworts,  which  the 
atmosphere,  now  of  greatly  diminished  density, 
and  containing  little  carbonic  acid,  supports 
but  sparingly :  Parmelias,  Lecideas,  and  Le- 
prarias  with  their  many- coloured  sporules,  form 
the  flora  of  this  inhospitable  zone.  Patches  or 
islets  of  lately  fallen  snow  now  begin  to  cover 
the  last  efl!brts  of  vegetable  life,  and  then, 
sharply  defined,  the  line  of  eternal  ice  begins. 
Through  the  white,  and  probably  hollow,  bell- 
shaped  summits  of  the  mountains,  the  subter- 
ranean powers  strive,  but  mostly  in  vain,  to 
break  through.  Where  they  have  succeeded  in 
estabUshing  a  communication  with  the  atmo- 
sphere, through  cauldron-shaped  fiery  throats  or 
far  penetrating  chasms,  they  rarely  send  forth 
lava,  as  in  the  Old  World,  but  carbonic  acid, 
hydrosulphurets,  and  hot  watery  vapour  in 
abundance. 

So  magnificent  a  spectacle,  in  its  first  assault 
upon  the  rude  natural  feelings,  could  excite 
nothing  but  wonder  and  dull  amazement  in  the 
mind  of  natives  of  the  tropical  world.  The  in- 
timate connection  of  grand  periodically  recur- 
ring phenomena,  and  the  simple  laws  according 
to  which  these  phenomena  are  grouped  zone- 
wise,  present  themselves  there,  above  all  other 
places,  with  signal  clearness  to  the  senses  of 
mankind ;  but  from  causes  which,  in  many  por- 
tions of  this  highly  favoured  quarter  of  the 
earth,  oppose  the  local  development  of  high 
civilization,  all  the  advantages  of  this  more  fa- 
cile study  of  these  laws  have  remained  with- 
out effect — so  far,  at  least,  as  historical  data  en- 
able us  to  conclude.  The  profound  researches 
of  recent  times  have  made  it  more  than  doubt- 
ful that  the  peculiar  seat  of  the  Indian  civiliza- 
tion— one  of  the  fairest  flowers  in  the  history 
of  humanity,  the  south-eastern  spread  of  which 
has  been  so  ably  investigated  by  William  von 
Humboldt(0 — was  within  the  limits  of  the  trop- 
ics. Airyana  Baedjo,  the  ancient  Zend  coun- 
try, lay  to  the  north-west  of  the  upper  Indus  ; 
and  after  the  religious  disunion  or  secession  of 
the  Iranians  from  the  Brahminical  institutes, 
and  their  separation  from  the  Hindoos,  the  ori- 
ginal common  language  acquired  its  distin- 
guishing features,  and  the  social  institutions 
gained  their  peculiar  characters  in  Magadha(^), 
or  Madhya  Desa,  between  the  little  Windhya 
and  the  Himalaya  chain. 

A  clear  insight  into  the  operations  of  the 
physical  agencies  was  first,  although,  indeed, 
at  a  much  later  period,  acquired  by  the  races 
that  people  the  temperate  zone  of  our  northern 
hemisphere,  and  this,  in  spite  of  all  the  obsta- 
cles which,  under  higher  latitudes,  complicate 
the  phenomena  of  the  atmosphere,  and  render 
difficult  the  discovery  of  general  laws  in  the 
climatic  distribution  of  organic  beings.    From 


hence  has  a  knowledge  of  the  character  of  trop- 
ical countries,  and  of  countries  situated  near 
the  tropics,  been  brought  by  larger  movements 
of  masses  of  mankind,  or  by  individual  foreign 
settlers — a  transplantation  of  scientific  culture 
which  has  had  a  like  beneficial  influence  on  the 
intellectual  existence  and  industrial  prosperity 
both  of  colonies  and  parent  states.  And  here 
we  touch  the  point  at  which,  in  the  commerce 
betwee^n  mind  and  the  world  of  sense,  another 
form  of  enjoyment  is  associated  to  that  which 
depends  on  excitement  of  the  feehngs — an  en- 
joyment of  nature  which  springs  from  ideas  ; 
the  point  at  which,  in  the  war  of  the  conflicting 
elements,  the  orderly,  the  legitimate,  is  not 
merely  surmised  or  suspected,  but  is  positively 
known  by  force  of  reason  :  the  point  at  which 
man,  as  the  immortal  poet  has  it — 

Amidst  fleeting  phenomena,  seeks  the  stable  pole. (9) 

To  follow  this  variety  of  enjoyment,  spring- 
ing from  ideas,  to  its  source,  we  have  only  to 
cast  our  eye  back  upon  the  rise  and  progress 
of  the  history  of  the  philosophy  of  nature  ;  in 
other  words,  of  the  ancient  doctrine  of  Cosmos. 

An  indefinite  dread  sense  of  the  unity  of  the 
powers  of  nature,  of  the  mysterious  bond  which 
connects  the  sensuous  with  the  super-sensuous, 
is  common  even  among  savage  communities ; 
my  own  travels  have  satisfied  me  that  this  is  so. 
The  world  which  is  revealed  to  man  through  the 
senses,  blends,  often  without  his  consciousness, 
with  the  world  which,  in  obedience  to  his  inter- 
nal promptings,  he  creates  in  the  guise  of  a 
realm  of  wonders  in  his  own  interior.  The 
latter,  however,  is  nothing  like  a  true  reflection 
of  the  former  -,  for  however  impotent  the  Ex- 
ternal be  to  dissever  itself  from  the  Internal, 
still  creative  fancy,  and  the  disposition  to  rep- 
resent in  concrete  shapes  the  significant  in  phe- 
nomena, proceed  incessantly  in  their  workings, 
even  among  the  rudest  nations.  That  which 
presents  itself  to  single  more  gifted  individuals 
as  the  rudiments  of  a  natural  philosophy,  as  an 
induction  under  the  guidance  of  reason,  ac- 
quires existence  as  the  product  of  instinctive 
susceptibilities  among  whole  tribes  of  men.  In 
this  way,  out  of  the  depth  and  activity  of  blind 
feeling,  is  also  eliminated  the  first  impulse  to  ad- 
oration, the  sanctification  of  the  preserving  as 
of  the  destroying  powers  of  nature  ;  and,  if 
man,  in  passing  through  the  different  phases 
of  his  progress,  now  feels  himself  less  fettered 
to  the  earth,  and  rising  by  degrees  to  mental 
freedom,  he  can  be  satisfied  no  longer  with  a 
mere  indefinite  feeling,  an  obscure  suspicion  of 
the  unity  of  the  natural  forces.  The  faculty  of 
thought,  with  its  attributes  of  analysis  and  ar- 
rangement, now  asserts  its  rights,  and  growing 
in  the  same  measure  as  the  human  kind  im- 
proves, in  presence  of  the  plenitude  of  life  that 
flows  throughout  creation,  the  eager  desire  to 
penetrate  more  deeply  into  the  causal  connec- 
tion of  phenomena  is  experienced. 

It  is  extremely  difficult  to  obtain  speedy  and, 
at  the  same  time,  certain  satisfaction  to  such  a 
desire.  From  imperfect  observations,  and  still 
more  imperfect  inductions,  erroneous  views  ot 
the  character  of  the  natural  forces  arise  ;  views 
which,  embodied  and  fixed  in  significant  words 
and  phrases,  distribute  themselves,  a  common 
inheritance  of  fancy,  through  all  classes  of  a 
nation.    By  the  side  of  the  scientific  system  of 


introduction: 


nature,  another  is  then  seen  growing  with  an 
equal  growtli — a  system  of  unproven,  and,  in 
part,  entirely  mistaken  empirical  knowledge. 
Embracing  but  few  particulars,  this  kind  of 
empiricism  is  the  more  presuming,  because  of 
its  utter  ignorance  of  the  facts  by  which  it  is 
assailed.  Shut  up  within  itself,  it  is  unchan- 
ging in  its  axioms,  and  arrogant,  like  every  thing 
else  that  is  restricted  ;  whilst  enlightened  nat- 
ural science,  inquiring,  and  therefore  doubting, 
goes  on  separating  the  firmly  established  from 
the  merely  probable,  and  perfects  itself  daily 
through  the  extension  and  correction  of  its 
views. 

The  crude  heap  of  physical  dogmas  which 
one  age  transmits  to  and  forces  upon  another, 
is  not  merely  injurious  because  it  cherishes  in- 
dividual errors,  because  it  obstinately  presents 
indifferently  observed  facts  for  acceptance  ;  it 
does  more  than  this,  it  opposes  every  thing  like 
grand  or  comprehensive  views  of  the  fabric  of 
the  universe.  Instead  of  investigating  the  me- 
dium point  about  which,  despite  the  apparent 
unfettered  aspect  of  nature,  all  phenomena  os- 
cillate within  narrow  limits,  it  takes  cognizance 
of  the  exceptions  only  to  the  law ;  it  seeks  for 
other  wonders  in  phenomena  and  forms  than 
those  of  regulated  and  progressive  develop- 
ment. It  is  ever  disposed  to  presume  the  train 
of  natural  sequence  interrupted,  to  overlook  in 
the  present  all  analogy  with  the  past,  and,  tri- 
fling with  the  subject,  to  discover  the  cause  of 
some  fancied  disturbance  now  in  the  depths  of 
the  vault  of  heaven,  now  in  the  interior  of  the 
globe  we  inhabit.  It  leads  away  from  that  com- 
parative geognosy  which  Ritter's  great  and 
masterly  work  has  shown  can  only  acquire  any 
thing  like  completeness  when  the  whole  mass 
of  facts,  which  have  been  collected  in  all  the 
climates  of  the  earth,  comprehended  at  a  glance, 
stands  marshalled  at  the  disposal  of  the  combi- 
ning intellect. 

It  is  one  of  the  objects  of  these  discourses 
upon  nature,  to  correct  a  portion  of  the  errors 
which  have  sprung  from  rude  and  imperfect 
empiricism,  and  continue  to  live  on  among  the 
upper  classes  of  society,  associated  frequently 
with  distinguished  literary  tastes  and  acquire- 
ments, and  thereby  to  increase  the  relish  for 
nature  by  giving  a  clearer,  a  deeper,  insight  into 
her  constitution.  The  want  of  such  an  enno- 
bled relish  for  nature  is  generally  felt ;  for  a 
peculiar  character  of  the  age  we  live  in,  is  pro- 
claimed in  the  tendency  among  all  the  educated 
classes  to  enhance  the  pleasures  of  existence 
by  adding  to  the  store  of  ideas.  The  lively  in- 
terest which  is  taken  in  these  prelections  bears 
witness  to  the  prevalence  of  such  a  disposition. 

I  cannot,  therefore,  yield  any  place  in  my 
mind  to  the  solicitude  to  which  either  a  certain 
narrowness  of  understanding,  or  a  kind  of  sen- 
timental dulness,  appears  to  lead — the  solici- 
tude, namely,  that  nature  loses  aught  of  her 
magic,  of  her  charms  in  respect  of  mysterious- 
ness  and  grandeur,  by  inquiries  into  the  inti- 
mate constitution  of  her  forces.  The  forces  of 
nature,  indeed,  only  operate  magically,  in  the 
legitimate  sense  of  the  word,  shrouded,  as  it 
were,  in  the  gloom  of  some  mysterious  power, 
when  their  workings  lie  beyond  the  bounda- 
ries of  generally  ascertained  natural  conditions. 
The  observer  who  determines  the  diameters  of 


the  planets  with  a  heliometer,  or  a  prism  of 
double  refracting  spar(^°),  who  measures  the 
meridian  altitudes  of  the  same  star  for  a  series 
of  years,  who  discovers  telescopic  comets 
amidst  thickly  aggregated  nebulous  spots,  does 
not,  probably,  feel  his  fancy  more  excited  than 
the  descriptive  botanist,  whilst  he  is  counting 
the  divisions  in  the  calyx  and  corolla  of  a  flow- 
er, or  is  ascertaining,  in  the  structure  of  a  moss, 
the  state  of  distinctness  or  coalescence  of  the 
teeth  that  surround  the  seed  capsule  ;  but  meas- 
urements of  angles,  and  the  development  of 
numerical  relations,  the  careful  observation  of 
the  Individual,  prepares  the  mind  for  the  loftier 
knowledge  of  nature  as  a  whole,  and  leads  to 
the  discovery  of  the  laws  that  rule  the  universe. 
To  the  natural  philosopher,  who,  like  Young, 
and  Arago,  and  Fresnel,  measures  the  undula- 
tions of  unequal  length,  the  interferences  of 
which  strengthen  or  weaken  the  ray  of  light ; 
to  the  astronomer,  who,  by  the  space-piercing 
power  of  his  telescope,  studies  the  satellites  of 
Uranus  on  the  outermost  verge  of  our  system, 
or,  like  Herschel,  South,  and  Struve,  detects 
glimmering  points  of  brighter  light  in  the  col- 
oured double  stars  ;  to  the  initiated  eye  of  the 
botanist,  who  perceives  the  circular  movements 
of  the  sap-globules  so  conspicuous  in  the  Charas, 
in  almost  all  vegetable  cells,  and  who  finds  unity 
of  formation,  in  other  words,  enchainment  of 
forms,  in  species  and  natural  families — these 
cultivated  intellects  surely  look  into  the  depths 
of  heaven,  as  they  survey  the  flower-clad  sur- 
face of  the  earth,  with  a  grander  eye,  than  the 
observer  whose  intellectual  vision  is  not  yet 
sharpened  by  any  apprehension  of  the  enchain- 
ment of  phenomena.  We  cannot,  therefore,  as- 
sent to  the  proposition  of  the  eloquent  Burke, 
when  he  says,  that  "  out  of  the  uncertainty  of 
the  nature  of  things  alone,  do  admiration  and 
the  feeling  of  sublimity  arise." 

Whilst  vulgar  sense  conceives  the  stars  in- 
laid in  a  crystalline  vault,  the  astronomer  actu- 
ally extends  the  bounds  of  space  ;  for  if  he  cir- 
cumscribes the  cluster  of  stars,  of  which  our 
sun  is  one,  it  is  only  that  he  may  show  others 
and  others,  a  countless  multitude  of  groups  of 
suns,  the  infinite  depths  of  space,  till  vision  fails, 
still  studded  with  astral  systems  like  our  own. 
The  feeling  of  the  sublime,  in  so  far  as  it  seems 
to  spring  from  the  simple  contemplation  of  in- 
finite space,  is  closely  allied  to  that  rapt  mood 
of  the  mind  which,  in  the  realm  of  the  spiritual, 
in  abstract  converse  with  our  own  conscious- 
ness, arises  from  the  meditation  of  the  endless 
and  the  free.  Upon  this  affinity,  this  relation- 
ship of  sensuous  impressions,  depends  the  ma- 
gic, the  feeling  of  infinitude,  which  we  experi- 
ence when  we  are  gazing  over  the  shoreless 
ocean,  surrounding  some  isolated  mountain 
peak,  or  are  penetrating  the  depths  of  heaven- 
ly space  with  the  telescope,  and  resolving  neb- 
ulous specks  into  their  constituent  stars  ;  no- 
thing impresses  the  cultivated  imagination  more 
powerfully  than  spectacles  like  these. 

One-sided  treatment  of  the  physical  sciences, 
endless  accumulation  of  the  raw  material,  might 
indeed  appear  to  countenance  the  now  almost 
superannuated  objection,  that  scientific  knowl- 
edge must  of  necessity  chill  the  feelings,  quench 
the  creative  light  of  fancy,  and  so  interfere  with 
the  enjoyment  of  nature.    But  he  who  counte- 


INTRODUCTION. 


nances  this  idea,  in  the  stirring  times  in  which 
we  live,  very  certainly  misunderstands  the  joys 
of  that  higher  intelligence  which  is  the  appa- 
nage of  the  general  progress  of  human  society — 
of  that  tendency  of  the  mind  which  resolves 
multiplicity  into  unity,  and  loves  especially  to 
dwell  with  the  General  and  the  Exalted.  To 
taste,  to  enjoy  this  Exalted,  it  is  imperative 
that  the  individualities  which  have  been  the 
prize  of  the  carefully  cultivated  field  of  special 
natural  forms  and  natural  phenomena  be  care- 
fully kept  in  the  background  ;  he  who  has  him- 
self most  clearly  seen  their  importance,  and 
whom  they  have  most  safely  led  to  loftier 
views,  must  more  especially  hold  them  in  re- 
serve. 

To  the  groundless  fears  for  the  loss  of  an 
unfettered  enjoyment  of  nature,  under  the  in- 
fluence of  reflective  surveys,  or  scientific  scru- 
tinies of  her  domains,  may  be  associated  those 
which  are  derived  from  alarm  lest  a  due  meas- 
ure of  this  knowledge,  or  an  adequate  concep- 
tion of  its  bearings,  prove  unattainable  to  the 
mass  of  mankind.  In  the  wonderful  tissues  of 
organized  beings,  in  the  eternal  tendencies  and 
workings  of  the  living  powers,  each  new  and 
deeper  inquiry  seems  but  to  lead  to  the  en- 
trance into  a  new  labyrinth.  But  this  very 
multiplicity  of  untrodden  and  intricate  paths 
excites  a  kind  of  joyful  amazement  on  each 
successive  grade  of  science.  Each  natural  law 
which  reveals  itself  to  the  observer  leads  to 
the  inference  of  one  yet  higher  and  unknown  ; 
for  Nature,  as  Carus  well  says(^'),  and  as  the 
word  itself  was  understood  by  the  ancient 
Greeks  and  Romans,  "  is  the  Ever-becoming, 
the  Ever-engaged  in  fashioning  and  evolving." 
The  circle  of  organic  types  extends  the  wider 
the  more  the  earth  is  searched  over,  in  travels 
by  land  and  voyages  by  sea  ;  the  more  living 
organic  forms  are  compared  with  the  remains 
of  those  that  are  extinct,  the  more  the  micro- 
scope is  improved,  and  adds  to  the  empire  of 
the  eye.  In  the  multiplicity  and  changes  of 
organic  forms,  in  consonance  with  climatic  in- 
fluences, the  prime  mystery  of  all  formation  is 
incessantly  reproduced  ;  it  is  the  problem  of 
metamorphosis,  so  happily  developed  by  Go- 
ethe, upon  the  grandest  scale,  and  proclaims 
the  necessity  for  an  ideal  reference  of  organic 
forms  at  large  to  certain  elementary  types. 
With  an  extension  of  knowledge,  the  feeling 
o*  the  immeasurableness  of  the  life  of  nature 
IS  still  increased,  and  we  perceive  that,  neither 
in  the  solid  crust  of  the  globe,  nor  in  the  aerial 
covering  that  invests  the  solid,  neither  in  the 
depths  of  the  ocean,  nor  in  the  depths  of  heav- 
en, will  the  bold  scientific  conqueror(")  lack 
scope  for  his  inquiries  for  thousands  of  years 
to  come. 

General  views  of  the  Fashioned,  be  it  matter 
aggregated  into  the  farthest  stars  of  heaven, 
be  it  the  phenomena  of  earthly  things  at  hand, 
are  not  merely  more  attractive  and  elevating 
than  the  special  studies  which  embrace  partic- 
ular portions  of  natural  science  ;  they  further 
recommend  themselves  peculiarly  to  those  who 
have  little  leisure  to  bestow  on  occupation  of 
the  latter  kind.  The  descriptive  natural  scien- 
ces are  mostly  adapted  to  particular  circum- 
stances :  they  are  not  equally  attractive  at  ev- 
ery season  of  the  year,  in  every  country,  or  in 


every  district  we  inhabit.  The  immediate  in- 
spection of  natural  objects,  which  they  require, 
we  must  often  forego,  either  for  long  years,  or 
always  in  these  northern  latitudes  ;  and  if  our 
attention  be  limited  to  a  determinate  class  of 
objects,  the  most  graphic  accounts  of  the  trav- 
elling naturalist  afford  us  little  pleasure  if  the 
particular  matters,  which  have  been  the  spe- 
cial subjects  of  our  studies,  chance  to  be  pass- 
ed over  without  notice. 

As  universal  history,  when  it  succeeds  in  ex- 
posing the  true  causal  connection  of  events, 
solves  many  enigmas  in  the  fate  of  nations,  and 
explains  the  varying  phases  of  their  intellectu- 
al progress — why  it  was  now  impeded,  now  ac- 
celerated— so  must  a  physical  history  of  crea- 
tion, happily  conceived,  and  executed  with  a 
due  knowledge  of  the  state  of  discovery,  re- 
move a  portion  of  the  contradictions  which  the 
warring  forces  of  nature  present,  at  first  sight, 
in  their  aggregate  operations.  General  views 
raise  our  conceptions  of  the  dignity  and  gran- 
deur of  nature  ;  and  have  a  peculiarly  enlighten- 
ing and  composing  influence  on  the  spirit ;  for 
they  strive  simultaneously  to  adjust  the  con- 
tentions of  the  elements  by  the  discovery  of 
universal  laws,  laws  that  reign  in  the  most  del- 
icate textures  which  meet  us  on  earth,  no  less 
than  in  the  Archipelagos  of  thickly  clustered 
nebulae  which  we  see  in  heaven,  and  even  in 
the  awful  depths  of  space — those  wastes  with- 
out a  world.  General  views  accustom  us  to 
regard  each  organic  form  as  a  portion  of  a 
whole ;  to  see  in  the  plant  and  in  the  animal 
less  the  individual  or  dissevered  kind,  than  the 
natural  form,  inseparably  linked  with  the  ag- 
gregate of  organic  forms.  General  views  give 
an  irresistible  charm  to  the  assurance  we  have 
from  the  late  voyages  of  discovery  undertaken 
towards  either  pole,  and  sent  from  the  stations 
now  fixed  under  almost  every  parallel  of  lati- 
tude, of  the  almost  simultaneous  occurrence  of 
magnetic  disturbances  or  storms,  and  which 
furnish  us  with  a  ready  means  of  divining  the 
connection  in  which  the  results  of  later  obser- 
vation stand  to  phenomena  recorded  as  having 
occurred  in  bygone  times  ;  general  views  en- 
large our  spiritual  existence,  and  bring  us,  even 
if  we  live  in  solitude  and  seclusion,  into  com- 
munion with  the  whole  circle  of  life  and  activ- 
ity—with the  earth,  with  the  universe. 

Who — to  select  a  particular  instance  from 
the  realms  of  space — who,  that  has  paid  any 
attention  to  scientific  events  in  the  course  of 
the  last  few  years,  can  perceive,  without  a  gen- 
eral knowledge  of  the  ordinary  orbits  of  com- 
ets, how  pregnant  with  results  is  Encke's  dis- 
covery, that  a  comet,  which,  in  its  elliptical  or- 
bit, never  leaves  our  planetary  system,  reveals 
the  existence  of  a  fluid  controlling  its  centrifu- 
gal force  1  With  the  recent  spread  of  a  kind 
of  half-education,  which  attracts  scientific  con- 
clusions into  the  circle  of  social  amusement 
and  conversation,  but  so  commonly  distorts 
them,  we  have  seen  the  old  solicitude  revived 
about  a  collision  between  the  heavenly  bodies, 
threatening  danger  or  destruction  to  all,  and 
cosmic  influences,  in  an  altered  and  therefore 
more  deceitful  guise,  quoted  to  account  for  pre- 
sumed deteriorations  of  climates,  and  the  like. 
Clear  conceptions  of  nature,  though  they  may 
not  be  more  than  historical,  preserve  us  from 


INTRODUCTION. 


the  presumptions  of  dogmatizing  fancy.  They 
assure  us  that  Encke's  comet,  which  completes 
its  revolution  in  1200  days,  by  reason  of  the 
form  and  position  •f  its  orbit,  must  ever  be 
harmless  to  the  inhabitants  of  the  earth — as 
harmless  as  Halley's  comet,  the  great  comet 
of  1.759  and  1835,  with  its  period  of  76  years ; 
but  that  another  comet,  of  shorter  period,  Bie- 
la's,  to  wit,  with  its  course  of  six  years,  actu- 
ally crosses  the  orbit  of  the  earth,  though  it 
can  only  approach  us  nea.ly  when  its  perihelion 
falls  at  the  time  of  our  winter  solstice. 

The  quantity  of  caloric  which  one  of  the  plan- 
ets receives,  and  the  distribution  of  which  de- 
termines the  grand  meteorological  processes 
of  the  atmosphere,  is  modified  by  the  light- 
evolving  power  of  the  sun — the  property  of  its 
surface,  and  the  relative  position  of  the  sun 
and  the  planet ;  but  the  cyclic  changes  which 
the  form  of  the  earth's  orbit,  and  the  obliquity 
of  the  ecliptic,  undergo,  in  conformity  with  the 
general  laws  of  gravitation,  are  so  slow,  and 
confined  within  such  narrow  limits,  that  their 
influence  will  scarcely  be  perceptible  to  such 
instruments  as  we  now  possess  for  measuring 
temperature  in  the  course  of  several  thousand 
years.  Cosmic  causes  of  diminished  tempera- 
ture, of  lessened  fall  of  rain,  and  of  epidemic 
diseases,  which  were  much  canvassed  in  the 
middle  ages,  and  of  which  mention  has  again 
been  lately  made,  are  consequently  seen  to  be 
entirely  beyond  the  pale  of  actual  experience. 

If  I  would  quote  other  instances  from  phys- 
ical astronomy,  which  could  excite  no  interest 
without  a  general  knowledge  of  what  has  been 
already  observed,  I  would  refer  to  the  numer- 
ous instances  of  differently  coloured  double 
stars  which  move  in  ellipses  round  one  anoth- 
er, or  rather  around  their  common  centre  of 
gravity ;  to  the  periodical  rarity  of  spots  in  the 
sun ;  to  the  regular  appearance  of  innumerable 
falling  stars,  which  have  now  been  the  subject 
of  observation  for  so  many  years,  and  which 
are  in  all  probability  planetary  in  their  nature, 
circulating  round  the  sun,  and  crossing  the 
earth's  orbit,  in  their  course  on  the  12th  or 
13th  of  November,  and  also,  according  to  later 
observation,  on  the  10th  or  11th  of  August. 

In  the  same  way,  general  views  of  Cosmos 
will  alone  enable  us  to  perceive  the  connection 
betwixt  the  theory  of  the  pendulum  swinging 
in  air,  and  the  internal  density — I  might  say, 
the  degree  of  congelation  or  solidification — of 
our  globe,  a  theory  happily  completed  by  the 
acuteness  of  Bessel ;  betwixt  the  production  of 
crystalline  rocks  in  stratified  streams  of  lava 
upon  the  acclivities  of  still  active  volcanoes, 
and  the  endogenous  granitic,  porphyritic,  and 
serpentine  rocky  masses,  which,  forced  up  from 
the  interior  of  the  earth,  have  burst  through  the 
floetz  formations,  and  produced  various  effects 
upon  them— hardening  or  silicifying  them,  con- 
verting them  into  dolomite,  producing  drusy 
cavities,  filled  with  crystals,  &c.  ;  betwixt  the 
elevation  of  islands  and  conical  mountains, 
through  elastic  forces,  and  the  uplifting  of 
mountain  chains  and  entire  continents — a  con- 
nection which  has  been  acknowledged  by  the 
greatest  geologist  of  our  age,  Leopold  von  Buch, 
and  illustrated  by  a  series  of  admirable  observa- 
tions. Such  upheavings  of  granular  mountain 
masses  and  floetz  strata,  as  have  even  lately 


been  witnessed  over  a  vast  extent  of  the  coast 
of  Chili,  in  connection  with  an  earthquake, 
show  us  how  possible  it  is  that  the  marine 
shells,  which  Bonpland  and  I  discovered  on  the 
slopes  of  the  Andes,  at  an  elevation  of  14,000 
feet  above  the  level  of  the  sea,  were  brought 
thither,  raised  from  the  bed  of  the  ocean  by 
volcanic  forces,  not  by  any  general  flood  that 
overspread  the  surface  as  it  now  presents  itself 
to  us. 

By  Plutonism,  or  Vulcanism,  taking  either 
word  in  its  most  general  sense,  and  using  it  not 
only  with  reference  to  the  earth,  but  also  to  its 
satellite,  the  moon,  I  mean  the  reaction  which 
the  interior  of  a  planet  exerts  upon  its  crust. 
He  who  is  unacquainted  with  the  observations 
that  have  been  made  on  the  gradual  rise  of  tem- 
perature, as  the  crust  of  the  earth  is  penetrated 
more  deeply  (observations  which  have  led  dis- 
tinguished naturalists  to  conclude  that  at  the 
depth  of  five  geographical  miles  below  the  sur- 
face, a  temperature  adequate  to  keep  granite  in 
a  state  of  fusion  prevails"),  is  not  prepared  to 
appreciate  many  recent  observations  on  the 
simultaneousness  of  the  eruptions  of  volcanoes, 
separated  by  vast  extents  of  country,  on  the 
limits  of  the  circles  within  which  earthquakes 
are  likely  to  be  felt,  on  the  permanence  of  the 
temperature  of  hot  mineral  springs,  and  on  the 
difference  of  temperature  of  the  water  in  Ar- 
tesian wells  of  different  depths.  And  yet  this 
knowledge  of  the  internal  temperature  of  the 
earth  throws  a  feeble  light  upon  the  primary 
history  of  our  planet.  It  proclaims  the  possi- 
bility at  a  former  epoch  of  the  general  diffusion 
of  a  tropical  climate  over  the  surface  of  the 
globe,  as  a  consequence  of  heat  inherent,  arid 
of  clefts  pouring  forth  heat,  in  the  lately  con- 
creted and  oxidated  crust  of  the  earth.  It  re- 
minds us  of  a  state  of  things  in  which  the  tem- 
perature of  the  atmosphere  may  have  been 
more  intimately  connected  with  the  reaction  of 
the  interior  upon  the  exterior,  than  with  the 
position  of  the  axis  of  revolution  of  our  planet 
to  the  great  central  mass  of  our  system,  the 
sun. 

Numerous  productions  of  the  tropics  are  now 
dug  up  by  eager  geologists  from  their  tombs  in 
the  temperate  and  cooler  regions  of  the  earth  : 
coniferous  vegetables,  trunks  of  palm  trees, 
erect  as  when  they  grew,  arborescent  ferns, 
goniatites,  and  fishes  with  rhomboidal  pearly 
scales,  in  the  old  coal  formations(**) ;  skeletons 
of  colossal  crocodiles,  long-necked  plesiosauri- 
ans,  the  scales  of  planulites,  and  the  stems  of 
cicadeae,  in  the  Jura  limestone  ;  polythalamians 
and  bryozoa  in  chalk,  in  several  instances  iden- 
tical with  species  still  existing  in  our  seas  ; 
vast  agglomerations  of  infusory  animalcules,  as 
brought  to  light  by  Ehrenberg's  all-animating 
microscope,  in  beds  of  tripoli,  semicpal  and  si- 
liceous sinter  (1)  (Kieselguhr) ;  bones  of  hyenas, 
lions,  and  elephantine  pachydermatous  animals, 
lying  exposed  in  caverns,  or  covered  merely 
with  a  layer  of  sand  or  mud.  With  a  compe- 
tent knowledge  of  other  natural  phenomena, 
these  productions  do  not  remain  objects  of 
mere  idle  curiosity  and  wonder  ;  they  become 
more  worthily  the  occasion  of  much  varied  and 
interesting  reflection. 

In  the  multiplicity  of  objects  which  I  have 
thus  cursorily  enumerated,  the  question  pre- 


10 


INTRODUCTION. 


sents  itself:  whether  general  views  of  nature 
can  be  brought  to  anything  like  precision  with- 
out deep  and  earnest  study  of  the  several  de- 
partments of  natural  science — natural  history, 
natural  philosophy,  and  physical  astronomy  1 
Here  it  is  proper  to  distinguish  carefully  be- 
twixt the  teacher,  who  makes  selections  and 
delivers  an  account  of  results,  and  the  pupil, 
who  receives  the  account  as  something  pre- 
sented to  him  not  investigated  for  himself.  For 
the  former,  the  most  intimate  knowledge  of 
specialities  is  indispensably  necessary ;  he  must 
have  long  familiarised  his  mind  with  the  several 
sciences,  he  must  himself  have  taken  the 
length  and  the  breadth  of  things,  observed  and 
made  experiments,  before  he  can,  with  any 
confidence  or, propriety,  venture  on  a  picture  of 
nature  as  a  whole.  The  entire  bearings  of  the 
problems  whose  investigation  lends  such  attrac- 
tions to  the  physical  history  of  the  world  are 
perhaps  scarcely  to  be  comprehended  in  all 
their  clearness  where  special  preliminary  knowl- 
edge is  wanting ;  although,  without  it,  the 
greater  number  of  the  propositions  can  still  be 
satisfactorily  discussed.  If  the  great  picture 
of  nature  be  not  presented  with  its  outlines 
equally  clear  and  sharp  in  every  part,  it  will 
still  be  found  sufficiently  true  and  attractive  to 
enrich  the  mind  with  ideas,  and  to  arouse  and 
fructify  the  imagination. 

It  has  been  made  matter  of  reproach — and 
perhaps  with  some  propriety — that  the  scien- 
tific works  in  our  language  do  not  sufficiently 
separate  the  General  from  the  Particular — the 
review  of  actually  established  facts  from  the 
narrative  of  the  means  by  which  the  results 
have  been  obtained.  This  imputation  has  led 
the  greatest  poet  of  our  age(")  humorously  to 
say,  that  "  the  Germans  possess  the  faculty  of 
making  the  sciences  inaccessible."  But  the 
scaffisld  left  standing,  we  are  hindered  from  ob- 
taining a  clear  view  of  the  building.  And  who 
will  doubt,  that  the  physical  law  in  the  distri- 
bution of  the  continental  masses,  which  assume 
a  pyramidal  shape  towards  the  south,  whilst 
towards  the  north  they  spread  out  into  vast 
bases — a  law  by  which  the  division  of  climates, 
theprevalenceofparticular  winds,  the  extension 
of  tropical  vegetable  forms  into  the  temperate 
northern  zones,  is  explained  in  the  most  satis- 
factory manner — can  be  understood  without 
reference  to  the  trigonometrical  surveys,  and 
the  astronomical  determinations  of  precise  ge- 
ographical positions,  by  which  the  dimensions 
of  the  pyramids  referred  to  have  been  ascer- 
tained 1  In  the  same  way,  we  learn  from  phys- 
ical geography,  that  the  equatorial  axis  of  our 
planet  is  greater  than  the  polar  axis  by  a  cer- 
tain number  of  miles,  that  the  southern  hemi- 
sphere is  not  flattened  in  a  greater  degree  than 
the  northern  hemisphere,  &c.,  without  its  be- 
ing necessary  to  narrate  at  length  how,  by 
measurements  of  degrees  of  the  meridian,  and 
experiments  with  the  pendulum,  the  figure  of 
the  earth  has  been  finally  determined  to  be  that 
of  an  irregular  spheroid  of  revolution  in  an  el- 
lipsis ;  and  how  this  figure  is  reflected  in  the 
motions  of  our  satellite,  the  moon. 

Our  neighbours  on  the  other  side  of  the  Rhine 
possess  an  immortal  work,  Laplace's  "  Sys- 
teme  du  Monde,"  in  which  the  results  of  the 
most  profound  mathematico-astronoiuical  in- 


vestigations of  the  phenomena  of  past  centunes 
are  luminously  presented,  freed  from  the  indi- 
vidualities of  the  demonstration.  The  struc- 
ture of  the  heavens  there  jjresents  itself  as  the 
simple  solution  of  a  great  problem  in  mechan- 
ics. Yet  no  one  has  ventured  to  charge  the 
"  Exposition  du  Systeme  du  Monde"  with  want 
of  depth,  because  of  its  form.  The  separation 
of  the  Dissimilar  in  views,  of  the  General  from 
the  Special,  is  not  merely  useful  in  facilitating 
the  acquisition  of  knowledge  ;  it  farther  gives 
an  elevated  and  earnest  character  to  the  treat- 
nient  of  natural  science.  As  from  a  higher  sta- 
tion we  overlook  larger  masses  at  once,  so  are 
we  pleased  mentally  to  grasp  what  threatens 
to  escape  the  powers  of  our  senses.  If  the 
successful  cultivation  of  every  branch  of  natu- 
ral science  in  recent  times,  appear  especially 
calculated  to  extend  the  study  of  particular  de- 
partnients — the  chemical,  the  physical,  the  phys- 
iological, &c. — the  progress  made  in  each  will 
nevertheless  contribute  in  an  eminent  degree 
to  abridge  and  render 'easy  the  way  to  the  at- 
tainment of  general  principles. 

The  more  deeply  we  penetrate  into  the  es- 
sence of  the  natural  forces,  the  more  do  we 
perceive  the  connection  of  phenomena,  which, 
severally  and  superficially  regarded,  seemed 
long  to  resist  every  attempt  at  co-ordination 
and  arrangement ;  the  more  do  we  see  simpli- 
city and  brevity  possible. 

It  is  a  certain  indication  of  the  extent  and 
value  of  the  discoveries  which  were  to  be  look- 
ed for  in  any  science,  when  the  facts  present 
themselves  as  still  unconnected,  almost,  as  it 
seems,  without  any  thing  like  mutual  reference, 
and  when  several  of  them,  the  fruit  of  the  same 
degree  of  careful  observation,  even  appear  con- 
tradictory or  subversive.  We  stand  at  thiij 
time  in  a  state  of  lively  expectation  in  regard 
to  meteorology,  to  some  of  the  departments  of 
optics,  and  especially,  since  Melloni  and  Fara- 
day came  upon  the  stage,  to  the  radiation  of 
heat  and  electro-magnetism.  The  field  of  brill- 
iant discovery  here,  has  certainly  not  yet  been 
exhausted,  although  a  very  remarkable  con- 
nection of  electrical,  magnetical,  and  chemical 
phenomena  has  undoubtedly  been  developed  in 
the  voltaic  pile.  And  who  shall  guarantee  us 
that  the  entire  number  of  the  vital  forces  effi- 
cient in  the  universe  has  been  fathomed  1 

In  my  mode  of  considering  the  scientific  treat- 
ment of  a  general  description  of  creation,  I 
make  no  question  of  that  unity  which  is  arrived 
at  by  induction  from  a  few  fundamental  princi- 
ples supplied  by  reason.  What  I  entitle  a  Phys- 
ical HisTOEY  OF  Creation — in  other  words,  a 
comparative  natural  history  of  the  earth  and 
heavens — consequently,  makes  no  pretensions 
to  the  rank  of  a  rational  Science  of  Nature  ; 
it  is  a  simple  consideration  of  the  phenomena 
that  are  known  empirically,  or  by  experience, 
as  a  natural  whole.  With  the  entirely  object- 
ive constitution  of  my  mind,  it  is  under  such 
restrictions  alone  that  the  history  of  creation 
fulls  within  the  scope  of  the  inquiries  which 
have  exclusively  occupied  me  in  the  long  course 
of  my  scientific  life.  I  do  not  venture  upon  a 
field  that  is  strange  to  me,  and  that  will  prob- 
ably be  cultivated  to  better  purpose  by  another. 
The  unity  attainable  in  such  a  history  of  crea- 
tion as  I  propose  to  exhibit,  is  no  more  thaa 


INTRODUCTION. 


11 


that  which  historical  representations  in  gener- 
al can  hope  to  achieve.  Details,  whether  as  to 
the  form  or  arrangement  of  natural  things,  no 
more  than  in  reference  to  the  struggles  of  man 
with  the  elements,  or  the  wars  of  one  nation 
against  another — all,  in  short,  that  falls  within 
the  sphere  of  mutability  and  true  accident — can- 
not be  derived  or  built  up  from  a  priori  concep- 
tions. The  natural  history  of  the  earth,  and 
universal  history,  consequently,  stand  on  the 
same  grade  of  the  empirical  ladder ;  but  a  lu- 
minous treatment  of  either,  a  rational  arrange- 
ment of  natural  phenomena  and  of  historical 
incidents,  impresses  us  deeply  with  a  belief  in 
an  old  inherent  necessity,  which  rules  all  the 
operations  both  of  the  spiritual  and  material 
forces  within  circles  eternally  reproduced  and 
only  periodically  contracted  or  enlarged.  This 
necessity,  indeed,  is  the  very  essence  of  nature ; 
it  is  nature  herself,  in  the  two  spheres  of  her 
being — the  material  and  the  spiritual — and  it 
leads  to  clearness  and  simplicity  of  view,  to  the 
discovery  of  laws  which,  in  experimental  sci- 
ence, present  themselves  as  the  ultimate  term 
in  human  inquiries. 

The  study  of  every  new  science,  especially 
of  one  which  embraces  the  infinite  field  of  cre- 
ation, the  universe  at  large,  may  be  compared 
to  a  journey  into  a  foreign  country.  Before 
undertaking  such  an  expedition  in  company, 
we  inquire  as  to  its  feasibility  ;  we  measure  our 
own  powers  of  endurance,  and  we  look  with  a 
suspicious  eye  at  the  powers  of  our  intended 
companions,  with  the  perchance  unjust  anxie- 
ty lest  they  prove  impediments  in  the  way. 
But  the  times  in  which  we  live  diminish  the 
difficulties  of  the  enterprise,  and  my  confidence 
in  ultimate  success  is  based  on  the  brilliant  po- 
sition now  occupied  by  natural  science  itself, 
whose  increasing  stores  may  now  be  said  to 
add  less  to  the  amount  than  to  the  enchain- 
ment of  observation.  The  general  results, 
which  so  powerfully  interest  every  cultivated 
mind,  have  been  wonderfully  augmented  since 
the  end  of  the  eighteenth  century.  Facts  now 
stand  less  insulated ;  numerous  gaps  between 
different  orders  of  beings  and  phenomena  have 
been  filled  up  ;  points  which  had  remained  in- 
explicable to  the  inquiring  spirit  at  home,  with- 
in the  narrower  circle  of  experience  accessible 
to  it,  are  frequently  made  clear  by  journeys  un- 
dertaken into  the  remotest  regions  of  the  earth. 
Vegetable  and  animal  forms  that  long  appeared 
isolated,  now  appear  connected  by  intermedi- 
ate links  or  transition  forms.  A  general  con- 
catenation, not  in  simple  linear  directions  only, 
but  in  reticulate  or  more  intricate  modes,  ac- 
cording to  the  higher  development  or  the  ar- 
rest of  certain  organs,  according  to  relative  pre- 
ponderance in  the  several  parts  or  systems,  now 
presents  itself  to  the  mind  of  the  enlightened 
naturalist.  Appearances  of  stratification  in  tra- 
chytic  syenite  or  porphyry,  in  green  stone  and 
serpentine,  which  are  doubtful  in  Hungary,  so 
rich  in  gold  and  silver,  in  the  platina  districts 
of  the  Ural  chain,  or  deeper  into  Asia,  in  the 
south-western  Altai,  are  unexpectedly  cleared 
up  by  geological  observations  in  the  lofty  pla- 
teaus of  Mexico  and  Antioquia,  and  in  the  val- 
leys of  Choco.  The  materials  which  universal 
geography  employs  are  not  indiscriminately  ac- 
cumulated.   In  the  present  times,  in  virtue  of 


the  tendency  which  their  individual  character 
impresses  upon  them,  it  is  admitted  that  new 
facts  are  only  pregnant  with  future  good,  when 
the  traveller  is  familiar  with  the  actual  state 
and  requirements  of  the  science  whose  bound- 
ary he  pretends  to  widen  ;  when  ideas,  in  oth- 
er words,  insight  into  the  spirit  of  nature,  guide 
the  taste  for  observation  and  collection. 

Through  this  direction  of  the  study  of  nature, 
through  the  happy,  but,  at  the  same  time,  often 
too  readily  satisfied  taste  for  general  results, 
can  a  very  considerable  portion  of  natural  sci- 
ence be  made  the  common  property  of  cultiva- 
ted humanity,  and  this  with  a  full  sense  of  the 
import  and  form,  of  the  grandeur  and  worth  of 
the  subject,  altogether  different  from  that  pop- 
ular science  which  was  held  sufficient  for  the 
world  at  large  up  to  the  end  of  the  last  centu- 
ry. Let  him,  therefore,  whom  circumstances 
permit  to  escape  from  time  to  time  from  the 
narrow  circle  of  his  every-day  occupations,  la- 
ment that  he  has  "  remained  so  long  a  stranger 
to  nature,  unconscious  of  her  charms,"  and 
learn,  that  in  the  contemplation  of  her  grandeur 
and  freedom,  there  dwells  the  purest  delight 
which  exalted  intelligence  can  obtain  for  man. 
The  study  of  general  natural  science,  indeed, 
awakens  organs  in  our  interior  that  have  long 
slumbered.  We  enter  upon  a  new  and  more 
intimate  intercourse  with  the  external  world, 
and  are  brought  to  feel  a  larger  sympathy  with 
that  which  proclaims  at  once  the  industrial 
progress,  and  the  intellectual  improvement  of 
mankind. 

The  clearer  the  insight  we  obtain  into  the 
connection  of  phenomena,  the  more  readily  do 
we  emancipate  ourselves  from  the  error  of 
believing  that   every  department  of  natural 
knowledge  is  not  equally  important  in  the  cul- 
ture and  welfare  of  mankind,  whether  it  be  that 
department  which  measures  and  describes,  or 
chemical  inquiries,  or  the  investigation  of  the 
generally  diffused  physical  forces  of  matter.    In 
the  observation  of  a  phenomenon  which  seems 
at  first  to  stand  isolated  and  alone,  there  fre- 
quently lies  the  germ  of  a  great  discovery. 
When  Galvani  stimulated  the  nerves  of  sensa- 
tion by  the  contact  of  two  dissimilar  metals,  his 
most  intimate  friends  and  contemporaries  could 
never  have  expected  that  the  voltaic  pile,  with 
its  electricity  of  contaction,  would  one  day 
show  us  a  brilliant  metal  in  the  alkalis,  silvery 
in  its  appearance,  readily  inflammable,  and  so 
light  as  to  float  upon  the  surface  of  water ;  that 
the  same  arrangement  would  by  and  by  become 
the  most  powerful  instrument  in  analytical 
chemistry,  and  prove  at  once  a  thermoscope 
and  a  magnet.     When  Huyghens  began  to  in 
vestigate  the  optical  properties  of  double  re 
fracting  spar,  no  one  imagined  that  the  phe 
nomena  of  coloured  polarization  would  lead  om 
of  the  singularly  clear-sighted  natural  philoso 
phers  of  our  day('*)  to  discover  in  the  fragmen 
of  a  mineral  a  means  of  knowing  whether  thi 
light  of  the  sun  proceeded  from  a  solid  mass  o* 
from  a  gaseous  canopy ;  whether  comets  havo 
the  power  of  emitting  light  in  themselves,  or 
merely  reflect  the  light  they  receive  from  other 
sources. 

A  like  respect  for  every  department  of  the 
study  of  nature  is,  however,  especially  neces- 
sary in  the  present  times,  when  the  material 


M 


INTRODUCTION. 


wealth  and  the  increasing  welfare  of  the  na- 
tions is  so  closely  connected  with  a  more  dili- 
gent use  of  natural  productions  and  natural 
forces.  The  most  superficial  glance  at  the 
condition  of  Europe  in  these  days,  assures  us 
that  with  the  struggle  against  serious  odds,  any 
relaxation  of  effort  would  be  followed,  first  by 
diminution,  and  then  by  annihilation  of  national 
prosperity  ;  for  in  the  destiny  of  nations  it  is  as 
in  nature,  in  which,  as  Goethe  (")  says,  finely, 
"  there  is  neither  rest  nor  pause,  but  ever  move- 
ment andv  evolution,  a  curse  still  cleaving  to 
standing  still."  Nothing  but  serious  occupa- 
tion with  chemical,  mathematical,  and  natural 
studies,  will  defend  any  state  from  evils  assail- 
ing it  on  this  side.  Man  can  produce  no  effect 
upon  nature,  can  appropriate  none  of  her  pow- 
ers, if  he  be  not  conversant  with  her  laws,  with 
general  relations  according  to  measure  and 
number.  And  here,  too,  lies  the  power  of  pop- 
ular intelligence.  It  rises  and  falls  with  this. 
Science  and  information  are  the  joy  and  the 
justification  of  mankind  ;  they  are  portions  of 
the  wealth  of  nations,  sometimes  a  substitute 
for  material  wealth,  which  nature  has  in  many 
cases  distributed  with  so  partial  a  hand.  Those 
nations  which  have  remained  behind  in  gen- 
eral manufacturing  activity,  in  the  practical 
application  of  the  mechanical  arts,  and  techni- 
cal chemistry,  in  the  transmission,  growth,  or 
manufacture  of  raw  materials,  nations  among 
whom  respect  for  such  activity  does  not  per- 
vade all  classes,  must  inevitably  fall  from  any 
prosperity  they  may  have  attained ;  and  this  by 
so  much  the  more  certainly  and  speedily,  as 
neighbouring  states,  instinct  with  powers  of 
youthful  renovation,  in  which  science  and  the 
arts  of  industry  co-operate  or  lend  each  other 
assistance  mutually,  are  seen  pressing  forward 
in  the  race. 

The  taste  for  manufacturing  industry,  and 
for  those  portions  of  natural  science  which  bear 
upon  it  more  immediately — a  characteristic  of 
the  present  'age — can  in  nowise  be  prejudicial 
either  as  regards  philosophy,  antiquities,  or  his- 
tory, nor  quench  the  all-animating  flame  of  fan- 
cy, in  the  direction  of  the  liberal  arts.  Where 
all  the  offshoots  of  civilization  are  permitted  to 
expand  in  vigour,  under  the  protection  of  wise 
laws  and  free  institutions,  no  effort  of  mind  in 
any  one  direction  will  be  found  to  interfere 
with  its  aspirations  in  another  quarter.  Each 
presents  its  own  peculiar  fruit  to  the  common- 
wealth :  one,  the  means  of  maintenance  and 
comfort  to  the  citizen,  another,  the  product  of 
creative  fancy,  which,  more  durable  than  ma- 
terial wealth,  transmits  the  name  and  fame  of 
the  community  to  the  latest  posterity.  The 
Spartiates,  despite  the  austerity  of  the  Doric 
mind,  prayed  "  the  Gods  to  vouchsafe  them  the 
beautiful  associated  with  the  good."(**) 

As  in  those  higher  circles  of  ideas  and  feel- 
ings—in the  study  of  history,  of  philosophy,  and 
of  oratory — so  in  all  the  departments  of  natural 
science,  the  first  and  highest  aim  of  intellectu- 
al activity  is  one  that  is  internal  ;  namely,  the 
discovery  of  natural  laws,  the  establishment  of 
co-ordinate  members  in  the  images,  the  per- 
ception of  necessary  connection  between  all 
the  changes  that  happen  in  the  universe.  So 
much  of  this  science  as  flaws  over,  and  min- 
gles with  the  industrial  life  of  communities,  el- 


evating manufacturing  industry,  does  so  in  vir- 
tue of  the  happy  connection  in  human  things, 
by  which  the  true,  the  exalted,  and  the  beauti- 
ful, mix  unintentionally,  as  it  seems,  but  cer- 
tainly, with  the  useful,  and  co-operate  with  it 
in  bringing  about  results.  The  improvement 
of  agriculture  by  the  hands  of  freemen,  and  on 
lands  of  moderate  extent ;  the  flourishing  con- 
dition of  manufactures,  emancipated  from  op- 
pressive restrictions  ;  the  extension  of  com- 
mercial relations,  and  the  unimpeded  progiess 
of  mankind  in  mental  development  as  well  as  in 
their  social  institutions,  are  all  inseparably  con- 
nected, and  severally  and  powerfully  advance 
each  other.  The  impressive  picture  of  the  late 
history  of  the  world  forces  this  faith  upon  the 
minds  even  of  those  that  most  eagerly  oppose  it. 

Such  an  influence  of  natural  science  upon  the 
welfare  of  the  nations,  and  on  the  present  con- 
dition of  Europe,  can  receive  nothing  more 
than  a  passing  allusion  in  this  place.  The 
course  we  have  to  complete  is  so  vast  in  itself, 
that  it  would  not  become  me  to  depart  from  the 
main  object  we  have  in  view,  namely,  the  sur- 
vey OF  NATURE  AS  A  WHOLE,  and  intentionally 
to  widen  the  field  of  our  inquiries.  Accustom- 
ed to  wanderings  in  distant  lands,  I  have,  per- 
haps, without  this,  indicated  the  path  to  my 
fellow-travellers,  as  more  distinctly  traced  and 
more  attractive  than  they  will  find  it  in  fact. 
This  is  ever  the  way  with  those  who  take 
pleasure  in  guiding  others  to  the  tops  of  mount- 
ains :  they  praise  the  view,  though  perchance 
large  tracts  of  the  country  lie  hidden  in  mist. 
They  know  that  even  in  this  concealment  there 
dwells  a  certain  mysterious  charm ;  that  the 
misty  horizon  calls  up  the  image  of  the  sensu- 
ous infinite  in  the  mind,  a  picture  which,  as  I 
have  already  observed,  is  reflected  in  grave  and 
grand  tints  in  the  mind  and  affections.  From 
the  lofty  stand,  too,  from  which  we  propose  to 
make  our  general  survey  of  nature  on  the  basis 
of  science,  all  that  is  requisite  cannot  be  com- 
manded. In  natural  science,  much  yet  lies  but 
ill  defined,  and  much — and  shall  I  not  gladly 
own  to  this  in  entering  on  a  field  so  vast  1 — 
will  appear  indefinite  and  incomplete  only  be- 
cause every  thing  like  embarrassment  becomes 
doubly  detrimental  to  the  speaker,  who  feels 
himself  indifferently  at  ease  in  his  subject,  when 
separated  from  its  individualities. 

The  purpose  of  this  Introduction  was  not  to 
present  a  picture  of  the  importance  of  natural 
science,  a  thing  universally  admitted  ;  it  was 
rather  to  show  how,  without  detriment  to  the 
deepest  study  of  the  several  special  depart- 
ments of  natural  science,  a  higher  position  for 
physical  scientific  inquiry  may  be  won,  from 
which  all  the  forms  and  powers  of  things  shall 
be  seen  to  reveal  themselves,  in  the  guise  of  a 
natural  whole,  actuated  by  intrinsic  aptitudes. 
Nature  is  no  dead  aggregate ;  she  is,  "  to  the 
inspired  inquirer,"  (as  Schelling  grandly  ex- 
presses himself,  in  his  admirable  Discourse  on 
the  Fine  Arts),  "  the  holy,  the  eternally  crea- 
tive prime  mover  of  the  universe,  engendering 
and  evolving  all  things  out  of  her  pregnant 
self"    The  hitherto  imperfectly  seizoi  idea  of 

a  PHYSICAL  HISTORY  OF  THE  EARTH  CXpaudS,  UU- 

der  more  enlarged  views  and  the  comprehen- 
sion of  all  created  things  in  earth  and  heaven, 
into  the  idea  of  a  physical  history  of  thk 


INTRODUCTION. 


13 


tNivKRsE.  The  latter  of  these  titles  is  fashion- 
ed from  the  former.  But  it  is  the  history  of 
the  universe,  or  the  doctrine  of  Cosmos,  as  I 
conceive  it ;  by  no  means  an  encyclopaedic  ex- 
position of  the  most  general  and  important  re- 
sults derived  from  particular  natural  historical, 
natural  philosophical,  and  astronomical  books. 
Such  results  will  only  be  introduced  incidental- 
ly into  my  description,  and  be  used  as  mate- 
rials only  in  so  far  as  they  illustrate  the  con- 
nection and  co-operation  of  the  forces  of  the 
universe,  the  production  and  limitation  of  nat- 
ural phenomena.  The  study  of  the  distribu- 
tion of  organic  types  according  to  soil  and  cli- 
mate, the  geography  of  plants  and  animals,  is 
as  dissimilar  from  descriptive  botany  and  zo- 
ology, as  geological  knowledge  of  the  crust  of 
the  Earth  is  different  from  oryctognosy.  A 
physical  history  of  the  universe,  consequently, 
must  not  be  confounded  with  an  encyclopaedia 
of  the  natural  sciences.  In  our  survey  of  the 
Universe,  the  Individual  will  only  be  regarded 
in  its  relations  to  the  General,  and  the  higher 
the  point  of  outlook  now  indicated  is  assumed, 
the  more  will  this  survey  be  made  susceptible 
of  especial  treatment,  and  of  interesting  dis- 
cussion. 


Thought  and  Language,  however,  stand  in 
most  intimate  and  old  relationship  to  one  an- 
other. When  speech  adds  grace  and  clearness 
to  ideas,  when  its  picturesqueness  of  derivation 
and  organic  structure  favour  our  efforts  sharp- 
ly to  define  natural  phenomena  as  a  whole,  it 
scarcely  fails  at  the  same  time,  and  almost  un- 
consciously to  us,  to  infuse  its  animating  pow- 
er into  the  fulness  of  thought  itself  The  word 
is,  therefore,  more  than  the  mere  sign  and  form, 
and  its  mysterious  influence  still  reveals  itself 
most  strikingly  where  it  springs  among  free- 
minded  communities,  and  attains  its  growth 
upon  native  soils.  Proud  of  our  fatherland, 
whose  intellectual  unity  is  the  prop  and  stay  of 
every  manifestation  of  mental  power,  we  turn 
our  eyes  with  joy  upon  this  privilege  of  our  na- 
tive country.  Highly-favoured,  indeed,  may 
we  call  him  who  draws,  in  his  accounts  of  the 
phenomena  of  creation,  from  the  depths  of  a 
language,  which,  through  the  force  aad  unfet- 
tered application  of  intellect,  in  the  regions 
of  creative  fancy,  no  less  than  in  those  of 
searching  reason,  has  for  centuries  influenced 
so  powerfully  all  that  affects  the  deitinies  of 


i 


NOTES    TO   INTRODUCTION. 


J  (page  4.)— This  expression  is  borrowed  from  a  fine  de- 
scription of  a  forest  in  Bernardin  de  St.-Pierre's  Paul  and 
Virginia. 

8  (p.  5.)  —  These  comparisons  are  only  approximations. 
The  more  accurate  elements  (heights  above  the  sea-level) 
are  for  the   Schnee-  or  Riesen-koppe,  in  Silesia,  824 
toises,  according  to  Hallaschka ;  for  the  RiGi,  923  t.,  as- 
suming the  surface  of  the  Lake  of  Lucerne  to  be  223  t. 
(Eschmann's  Results  of  Trigonometrical  Measurements  in 
Switzerland  in  1840,  p  230) ;  for  Mount  Athos,  1060  t. 
(Capt.  Gaultier)  ;  for  Mount  Pilatus,  1180  t. ;  for  Etna, 
1700-4  t.,  or  10,874  English  feet,  after  Capt.  Smyth.     Ac- 
cording to  Sir  John  Herschel's  barometric  measurements, 
communicated  by  him  to  me  in  1825,  it  is  10,876  Eng.ft.  = 
1700-7  t. ;  and,  according  to  Cacciatore,  from  angular  meas- 
urements, and,  assuming  the  terrestrial  refraction  to  be  = 
0-076,  it  is  10,898  Eng.  ft.,  or  1,704  t.     For  the  ScHRECK- 
HORN,  2,093  t. ;   the  Jungfrau,  2,145  t.  (Tralles) ;   for 
Mont  Blanc,  according  to  the  results  discussed  by  Roger, 
2,467  t.  {Bibl.  Univ.  May  1828,  pp.  24— 53)  ;  whilst  Carlini 
determined  it,  from  Mont  Colombier,  in  1821,  at  2,460  t. ; 
and  Austrian  engineers,  operating  fron>Trelod  and  the  Gla- 
cier d'Ambin,  fixed  it  at  2,463  t.     The  actual  height  of  the 
Swiss  snowy  mountains  varies,  according  to  M.  Eschmann, 
about  3i  t.,  owing  to  the  variable  thickness  of  the  coating 
of  snow.     For  Chimborazo,  my  trigonometrical  measure- 
ments give  3,350  t.  (Humboldt,  Rec.  cTObs.  astr.  vol.  i.  p. 
Liii.) ;  for  Dhawalaoiri,  4,390  t.    All  these  mountain- 
heights  are  given  in  toises,  of  six  Paris  feet  each.     As  Blake 
and  Webb's  determinations  differ  by  70  t.,  I  must  here  re- 
mark that  the  measurements  of  Dhawalagiri  (or  White 
Mountains,  from  the    Sanscrit   dhwala,  white,   and  giri, 
mountain),  cannot  pretend  to  equal  accuracy  with  those  of 
Jawahir   (4,027  t.=  24,160  Par.   ft.  =  25,749  Eng.   ft.= 
7,848  metres),  founded  on  a  complete  trigonometrical  oper- 
ation [vide  Herbert  and  Hodgson,  in  Asiat.  Res.  vol.  xiv.  p. 
189 ;  and  Supp.  to  Encycl.  Brit.  vol.  iv.  p.  643).     I  have 
shown  in  another  place  {Ann.  des  Sciences  nat.  Mars  1825), 
that  the  height  of  Dhawalagiri  (4,391  t.  =  26,345  Par  ft.  = 
28,077  Eng.  ft.)  simultaneously  depends  on  several  imper- 
fectly settled  elements  of  astronomical  positions  and  azi- 
muths (Humboldt,  Asie  cent.  vol.  iii.  p.  282).     Still  more 
unfounded  is  the  surmise  that  some  snowy  peaks  of  the  Tar- 
tarian chain,  in  the  north  of  Tibet,  near  the  Kuenlun  chain, 
rise  to  the  elevation  of  30,000  Eng.  ft.   (4,691  t.,  nearly 
twice  that  of  Mont  Blanc),  or  at  least  to  29,000  Eng.  ft.  or 
4,535  t.  {vide  Capt.  Alexander  Gerard  and  John  Gerard's 
Journey  to  Boorendo  Pass  in  1840,  vol.  i.  pp.  143  <fc  311). 
Chimborazo  is  styled  "  only  one  of  the  highest  points  of  the 
Andes,"  since  the  learned  and  able  traveller,  Mr.  Pentland, 
in  1827,  during  his  memorable  expedition  to  Upper  Peru,  or 
Bolivia,  measured  two  mountains  east  of  Lake  Titicaca; 
namely,  Sorata  (3,948  t.  =  23,688  Par.  ft.)  and  Illimani 
(3,753 1.  =  22,518  Par.  ft.),  which  far  exceed  Chimborazo 
(3,350  t.  =23.100  Par.  ft.)  in  height,  and  nearly  approxi- 
mate to  Jawahir  f4,0-27  t.),  the  highest  of  the  hitherto  ac- 
curately measured   Himalayan   mountains.      Mont    Blanc 
',2,467  t.  =  14,802  Par.  fl.)  is,  therefore,  883  t.  lower  than 
Chimborazo,  and    Chimborazo  598  t.  lower  than    Sorata, 
which  is  79  t.  lower  than  Jawahir,  but  probably  443 1.  low- 
er than  Dhawalagiri.     The  measurements  in  this  note  may 
be  taken  as  more  accurate  from  being  given  in  various 
scales,  since  false  reductions  of  those  scales  have  led  to  er- 
roneous numerical  statements  in  Moslem  maps  and  profiles. 
Pentland's  more  recent  measurements  of  Illimani,  in  1838, 
gives  7,275  met.  =  3,732 1.  for  its  height,  diflTering  only  21 1. 
from  the  measurements  of  1827. 

3  (p.  5.) — The  absence  of  Palms  and  arborescent  ferns  iu 
the  temperate  zones  of  the  Himalaya  is  shown  in  Don's 
Flora  Nepaliensis  (1825),  as  also  in  the  lithographed  and  re- 
markable catalogue  of  Willich's  Flora  [ndica,—a.  catalogue 
•which  contains  the  enormous  number  of  7,683  almost  entire- 
ly phanerogamous  Himalayan  species,  although  not  yetsuffi- 
ciently  examined  and  classified.  We  as  yet  know  of  only 
one  species  of  palm,  Chamxrops  Martiana,  Wall.  (Plant. 
Asiat.  vol.  iii.  p.  5,  t.  211)  in  Nepaul  (lat.  26^°— 27^0;, 
5,00U  feet  above  the  sea,  in  the  shady  valley  of  Bunipa. 
The  splendid  arborescent  fern,  Alsophila  Brunoniana,  Wall. 
of  which  the  British  Museum  has  had  a  stem,  45  feet  long, 
since  the  year  1831,  does  not  come  from  Nepaul,  but  from 
the  mountains  of  Silhet,  north-east  of  Calcutta,  lat.  24°  50'. 
The  Nepaul  fern,  Peranema  cyathoides,  Don,  formerly 
Sphsropteris  barbata,  Wall.  (op.  cit  vol,  i.  p.  42,  t.  48),  is 


nearly  related  to  the  Cyathea,  of  which  I  saw  a  species,  30 
feet  high,  in  the  South  American  Missions  of  Caripe  ;  bu 
it  was  still  no  tree,  properly  so  called. 

4  (p.  5.)  —  Ribes  nubicola,  R.  glaciale,  R.  CTossularia. 
In  spite  of  a  declaration  of  the  ancients  on  "  Eastern  Asia" 
(StPdbo,  lib.  xi.  p.  510,  Cas.),  the  vegetation  of  the  Hima- 
layas is  characterized  by  8  species  of  Pinus,  25  oaks,  4  birch- 
es, 2  species  of  Aesculus  (the  100  feet  high  wild  chesnut- 
tree  of  Cashmir  is  inhabited  up  to  33°  N.  lat.  by  a  great 
white  ape  with  a  black  face — Charles  von  Hiigel,  Kashmir, 
1840,  part  ii.  p.  249),  7  maples,  12  willows,  14  roses,  3  straw- 
berry species,  7  Alpine  roses  (Rhododendra),  one  of  which 
is  20  feet  high,  and  many  other  Northern  forms.  Amongst 
the  Coniferae  we  find  the  Pinus  Deodwara,  or  Deodara  (prop- 
erly deivaddru,  god-timher,)  nearly  related  to  Pinus  Cedrus. 
Near  the  eternal  snows  the  Gentiana  venusta,  G.  Moorcrof- 
tiana,  Swertia  purpurescens,  S.  speciosa,  Paruassia  armata, 
P.  nubicola,  Paeonia  Emodi,  Tulipa  stellata,  display  their 
large  blossoms.  Even  next  to  the  peculiar  Hindoo  mount- 
ainous species  of  European  orders,  we  find  eight  genuine 
European  species,  as  Leontodon  taraxacum.  Prunella  vul- 
garis, Galium  Aparine,  Thlaspi  arvense.  The  heath,  al- 
ready mentioned  by  Saunders,  in  Turner's  Journey,  and 
which  has  even  been  confounded  with  Calluna  vulgaris,  is 
an  Andromeda — a  fact  of  great  importance  for  the  geogra- 
phy of  Asiatic  plants.  If,  in  this  note,  I  make  use  of  the 
unphilosophical  expression,  "European  forms, or  European 
species,  growing  wild  in  Asia,"  it  is  a  consequence  of  th* 
ancient  Ixjtanical  language,  which  very  arbitrarily  subjects 
the  idea  of  the  distribution,  or  rather  of  the  coexistence  of 
organic  forms,  to  the  historical  hypothesis  of  an  immigra- 
tion, even  premising  a  movement  from  west  to  east,  out  of 
prejudice  to  European  cultivation. 

6  (p.  5.) — The  snow-line  of  the  southern  declivity  of  the 
Himalayan  chain  is  2,030 1.  =  12,180  ft.  above  the  sea-level, 
whilst  on  the  northern  side,  or  rather  on  the  peaks  which 
rise,  in  30^°  to  32°  lat.,  above  the  Tartaro- Tibetan  table- 
land, it  is  2,600  t.  =  15,600  ft.,  the  snow-line  being  at  the 
height  of  only  2,470 1.  =  14,820  ft.  under  the  equator  in  the 
Quito  Andes.  I  have  deduced  this  result  from  comparing 
together  several  observations  of  Webb,  Gerard,  Herbert,  an<i 
Moorcroft.  Vide  my  two  Memoires  sur  les  montagnes  de 
VInde  of  1816  and  1820  in  the  Ann.  de  Chimie  et  de  Phy- 
sique, torn.  iii.  p.  303  ;  tom.  xiv.  pp.  6,  22,  50.  The  eternal 
snow-line  on  the  Tibelan  declivity  is  a  consequence  of  the 
radiation  of  heat  by  the  near  table-land,  of  the  serenity  of 
the  sky,  and  of  the  scanty  formation  of  snow  in  very  dry 
cold  air  (Humboldt,  Asie  cent.  tom.  iii.  pp.  281—326).  The 
conclusion,  in  regard  to  this  line  on  both  sides  of  the  Him- 
alayas, which  I  proposed  as  the  more  probable  one,  had  the 
sanction  of  Colebrooke's  great  authority.  "I  find,"  as  he 
wrote  to  me  in  June  1824,  *'  that  the  height  of  the  eternal 
snows,  according  to  the  materials  which  I  possess,  is  13,000 
English  feet  (=  2.033 1.).  On  the  southern  declivity,  under 
the  parallel  of  31°,  Webb's  measures  would  give  me  13,500 
Eng.  ft.  (=  2,111  t.),  or  500  feet  more  than  Captain  Hodg- 
son's observations.  Gerard's  measurements  perfectly  con- 
firm your  announcement,  that  the  snow-line  is  higher  on 
the  northern  than  on  the  southern  side."  Only  in  this  year 
(1840)  have  we  at  length  received,  through  Mr.  Lloyd,  a 
copy  of  the  entire  journal  of  both  the  brothers,  Gerard  (Nar- 
rative of  a  Journey  from  Caunpoor  to  the  Borrendo  Pass,  iu 
the  Himalaya,  by  Captain  Alexander  Gerard  and  John  Ge- 
rard, edited  by  George  Lloyd,  vol.  i.  pp.  291,  311,  320,  327, 
and  341).  A  great  deal  on  single  localities  is  comprised  in 
the  "  Visit  to  the  Ghatool,  for  the  purpose  of  determining 
the  line  of  perpetual  snow  on  the  southern  face  of  the  Him- 
alaya, in  August  1822;"  but,  unfortunately,  the  travellers 
always  confound  the  height  where  accidental  snow  falls, 
with  the  maximum  height  at  which  the  snow-line  rises  over 
the  Tibetan  plateau.  Captain  Gerard  distinguishes  the 
peaks  in  the  middle  of  the  plateau,  the  eternal  snow-line  of 
which  he  fixes  at  from  18,000  to  19,000  Eng.  ft.  (=  2,815  to 
2,971  t.),  and  the  northern  declivities  of  the  Himalayaa 
chain,  which  limit  the  passage  of  the  Sutlej,  and  where  the 
plateau  is  deeply  furrowed,  with,  of  course,  little  radiation. 
The  village  Tangno  is  placed  only  at  9,300  Eng.  ft. 
(=  1,454  t.),  whilst  the  plateau  about  the  sacred  lake,  Ma- 
nasa,  is  said  to  be  17,000  Eng.  ft.  (=  2,653  t.)  high.  Capt. 
Gerard  finds  at  the  break  in  the  chain,  that  the  snow  is 
500  Eng.  ft.  (=  78  t.)  lower  on  the,  northern  declivity  than 
on  the  southern  towards  India ;  on  which  latter  face  the 
snow-line  is  estimated  by  him  at  15,000  Eng.  ft.  (=  8,346 1.). 


le 


NOTES  TO  INTRODUCTION. 


The  botanical  relations  offer  the  most  striking  differences  be- 
tween the  Tibetan  table-land  and  the  southern  aspect  of  the 
Himalayan  chain.  In  the  latter,  the  harvest  (and  the  com 
is  often  cut  green)  extends  to  1,560  t.  only;  the  upper 
woody  limit,  with  tall  oaks  and  Dewadaru  firs,  to  1,870  t., 
low  dwarf  birches  to  2,030  t.  On  the  plateau,  Capt.  Ge- 
rard saw  pastures  up  to  2,660 1. ;  cereals  prosper  up  to 
2^200  t.,  and  eren  to  9,900 1. ;  tall  birches  to  2,200  t.  ;  un- 
derwood, for  fuel,  to  2660  t.,  that  is,  200  t.  higher  than  the 
eternal  snow-line  under  the  equator  at  Quito.  It  is  most 
desirable  that  travellers,  accustomed  to  general  views, 
should  re-determine  the  mean  altitude  of  the  Tibetan  table- 
land, which  I  assume  to  be  1,800  t.,  between  the  Himalaya 
and  Kuen-lUn,  as  also  the  relative  glacial  heights  on  the 
northern  and  southern  declivities.  Hitherto  estimates  have 
been  often  bonfounded  with  actual  measurements,  and  the 
heights  of  some  prominent  peaks,  with  that  of  the  table- 
land wherefrom  they  rise  (compare  Carl  Zimmermann's 
acute  hypsometric  remarks  in  his  "  Geog^phical  Analysis 
of  the  Map  of  the  Interior  of  Asia,"  1841 ,  p.  98).  Mr.  Lord 
directs  our  attention  to  a  contrast  between  the  heights  of 
eternal  snow  on  both  declivities  of  the  Himalaya  and  the 
Apine  chain,  Hindoo  Koosh.  "  In  the  latter,"  he  says, 
**  we  find  the  table-land  in  the  south,  and  the  altitude  of 
the  snow-line  is  consequently  greater  on  the  southern  de- 
clivity: the  reverse  of  the  Himalaya,  which  is  bounded  by 
warm  plains  on  the  north,  as  the  Hindoo  Koosh  is  on  the 
south."  However  considerable  the  critical  corrections  that 
may  be  required  for  these  several  details,  it  is  still  an  in- 
disputable fact,  that  the  wonderful  configuration  of  a  por- 
tion of  the  earth's  surface  in  the  interior  of  Asia  allows  to 
the  human  race  the  possibility  of  propagation,  food,  fuel, 
and  colonization,  at  a  height  above  the  sea-level,  which,  in 
almost  every  other  district  of  both  continents  (excepting  the 
parched,  snow-free  Bolivia,  where  Pentland  found  the  snow- 
line under  160—17^°  s,  lat.  at  the  mean  height  of  2,450  t. 
in  1838,)  is  eternally  covered  with  ice.  The  probable  dif- 
ferences of  the  north  and  south  declivities  of  the  Himalaya 
range,  in  regard  to  the  eternal  snow-line,  have  been  amply 
confirmed  by  the  barometric  measurements  of  Victor  Jacque- 
mont,  who  so  early  became  the  victim  to  his  noble  and  un- 
tiring zeal  {vide  his  "  Correspondance  pendant  son  Voyage 
dans  I'Inde,  1833,  tom.  i.  p.  299  ;  and  "Voyage  dans  I'lnde 
})endant  less  ann*es  1828  i  1832,  livr,23,  pp.  290,296,  299). 
"  The  eternal  snows,"  says  Jacquemont,  *'  descend  lower 
on  the  southern  than  on  the  northern  declivity  of  the  Him- 
ilaya,  and  their  limit  constantly  rises  as  we  advance  to  the 
north  of  the  border-chain  of  India.  On  the  Kioubrong  peak, 
4581  metres  high  (2863  t.),  according  to  Captain  Gerard,  I 
was  still  considerably  beneath  the  limit  of  the  eternal 
snows,  which  in  this  part  of  the  Himalaya  I  believed  (cer- 
lainly  too  great— Humboldt)  to  be  at  6,000  metres  =  3078 1." 
The  same  traveller  observes,  that,  to  whatever  height  we 
rise  on  the  southern  declivity,  the  climate  retains  the  same 
character,  the  same  division  of  seasons,  as  in  the  plains  of 
India.  "  The  summer  solstice  brings  the  same  showers  of 
rain,  which  uninterruptedly  last  until  the  autumnal  equi- 
nox. Only  at  Kashmir,  which  I  have  found  to  be  5,350 
Eng.  ft.  high,"  (=837  t.,  therefore  nearly  that  of  the  cities 
Merida  and  Popayan,)  "  begins  a  new  and  distinct  climate." 
—Jacquem.  Corresp.  tom.  ii.  pp.  58  and  74.  Leopold  von 
Buch  accurately  remarks  that  the  monsoons  do  not  impel 
the  moist  and  warm  sea-air  of  the  Indian  lowlands  across 
the  Himalayan  barrier  to  the  tramontane  Tibetan  district 
of  Ladak  and  Lhassa.  Carl  von  Hi}gel  estimates  the  height 
Df  the  valley  of  Kashmir  above  the  sea-level,  from  observa- 
tions of  the  boiling  point  of  water  (Part  ii.  p.  155,  ant. ; 
Journal  of  the  Geog.  Soc.  vol.  vi.  p.  215)  at  5,818  Eng,  ft. 
(=  910  t.).  In  this  perfectly  calm  and  almost  tempest-free 
ralley,  under  34<^  T  lat.,  the  snow  lies  many  feet  deep  from 
December  to  March. 
^  'P  5.}— See  generally  my  "  Essai  >ur  la  G^graphie 


des  Plantes  et  Tableau  Physique  des  Regions  equinoxrales,* 
1807,  pp.  80—88  ;  on  the  diurnal  and  nocturnal  oscillations 
of  temperature  in  the  ninth  plate  of  my  "  Atlas  giog.  et 
phys.  du  nouveau  Continent,"  and  the  tables  to  my  work, 
"De  distributione  geographica  plantarum  secundum  cdbU 
temperiem  et  altitudinem  montium,"  1817,  pp.  90—116;  the 
meteorological  portion  of  my  "  Asie  centrale,"  torn.  iii.  pp. 
212—214  ;  lastly,  the  more  recent  and  accurate  account  of 
the  height-decreasing  temperature  among  the  Andes  in  Boos- 
singault's  "  M6moire  sur  laprofondeur  A  laquelle  on  trouve 
la  couche  de  temperature  invariable  sous  les  tropiqaes," 
Ann.  de  Chimie  et  de  Phys.  1833,  tom.  liii.  pp.  225—247). 
The  essay  last  quoted  contains  the  determination  of  the 
height  and  mean  temperature  of  128  points,  from  the  sea- 
level  to  the  declivity  of  Antisana,  at  2,800 1.  height,  between 
the  aerial  temperatures  of  27°5  and  l©?  Cent.  (=  81^5  and 
350  Fahr.). 

7  (p.  6.)  — "On  the  Kawi  Language  in  the  island  of 
Java,  with  an  introduction  on  diversities  in  the  structure  of 
language,  and  their  influence  on  the  mental  development 
of  the  human  race,  by  William  v.  Humboldt,"  1836,  vol.  i. 
pp.  5—310, 

8  (p,  6.)— Respecting  the  proper  Madhjadftga,  vide  Las- 
sen's excellent  Indische  Alter thumskunde,  vol.  i.  p.  92.  The 
Chinese  term  South  Bahar  Mo-kie-thi,  meaning  the  part 
lying  south  of  the  Ganges. — Vide  Chy-Fa-Hian's  Foe-koue' 
hi,  1836,  p.  256.  Djambu-dwipa  is  entire  India,  sometimes 
comprehending  one  of  the  four  Buddhist  continents. 

9  (p.  6.)  —  Schiller's  Elegy,  Der  Spaziergang,  or  the 
Walk,  which  first  appeared  in  1795,  in  the  Horen  :— 

Within  his  silent  chamber,  casting  circles 
Pregnant  with  meaning,  sits  the  thoughtful  sage — 
Creative  mind  compelling  new  results :  — 
Testing  the  forces  that  inhere  in  matter, 
Proving  the  magnet's  wondrous  hate  and  love, 
Pursuing  sound  through  the  air,  the  ray  of  light 
Through  ether,  still  intent  on  finding  laws 
Amidst  the  incongruous  in  what  seems  chaace, 
Intent  on  making  out  the  stable  pole 
Amidst  the  flight  of  mere  phenomena. 

10  (p.  7,)— Arago's  ocular  micrometer,  a  happy  improTe- 
ment  upon  Rochon's  prismatic  or  double-refraction  microm- 
eter, vide  M.  Mathieu's  note  in  Delambre,  "  Hist,  de  I'Astr 
au  18™  siecle,"  1827,  p.  651. 

11  (p.  8.) — Cams  on  the  Elementary  Parts  of  the  Osse- 
ous aivd  Crustaceous  Frame-work  of  Animals,  1821,  p.  6. 

12  (p.  8.) — Plut  in  vit,  Alex.  Magn.  cap.  rii. 

13  (p.  8.) — The  melting-points  of  difficultly  fusible  sub- 
stances usually  assumed  are  too  high,  Mitscherlich's  al- 
ways accurate  researches  liniit  the  melting-point  of  granite 
to  1,3000  C.  =  2,372CF. 

14  (p.  9.) — Louis  Agassiz's  classical  work  on  fossil  fehes, 
•'  Recb.  sur  les  Poissons  fossiles,"  1834,  vol.  i.  p.  38 ;  vol. 
ii.  pp.  3,  28,  34,  Addit.  p.  6.  The  entire  species  Aniblyp- 
terus,  Agass.  nearly  related  to  Palaeoiiiscus  (Palaeothris- 
sum),  is  buried  beneath  the  Jura,  in  the  old  coal  formatbn. 
Scales,  which,  in  single  layers,  are  formed  like  teeth,  and 
are  covered  with  enamel,  from  the  Lepidoid  family  (Order 
GanoHdes),  belong,  after  Placoides,  to  the  oldest  forms  of 
fossil  fishes,  whose  now  living  representatives  are  found  in 
two  species,  Bichir  (Nile  and  Senegal)  and  Lepidosteus 
(Ohio). 

15  (p,  10.)  — Goethe's  "Aphorismen  Sber  Naturwissen- 
schaft"  (Works,  small  edit.  1833^  vol,  l.  p.  155.) 

16  (p.  11.) — Arago's  discovery  in  1811  (Delambre,  op.  cit. 
p.  652). 

IT  (p.  12.) — Goethe's  "  Aphoristisches  iiber  die  Natur" 
(op.  cit.  vol.  L.  p.  4). 

18  (p.  12.)— Pseudo-Plato,  Alcib.  ii.  p.  148,  ed,  Stepb.  ; 
Flut.  Instituta  laeosica,  p.  253,  cd.  Huttea. 


LIMITATION  AND   SCIENTIFIC   TREATMENT  OF  A  PHYSICAL 
HISTORY  OF  CREATION. 


In  the  general  views  with  which  I  have  open- 
ed my  prolegomena  to  a  survey  of  universal  na- 
ture, I  have  sought  to  explain,  and,  by  exam- 
ples, to  illustrate,  how  the  enjoyment  of  nature, 
diverse  in  its  intimate  sources,  may  be  enhan- 
ced through  clear  ideas  of  the  connection  of 
her  phenomena,  and  of  the  harmony  that  reigns 
among  her  actuating  forces.  It  will  now  be 
my  endeavour  to  enunciate  more  particularly 
the  spirit  and  leading  idea  of  the  following  sci- 
entific inquiry ;  carefully  to  separate  from  it  all 
that  is  foreign ;  and  with  comprehensive  brev- 
ity to  convey  the  scope  and  contents  of  the  doc- 
trine of  the  Cosmos  as  I  have  apprehended  and 
worked  it  out,  after  long  years  of  study  in  vari- 
ous climates  of  the  globe.  Let  me  flatter  my- 
self with  the  hope  that  such  an  exposition  will 
bear  me  out  in  the  bold  title  I  have  given  my 
work,  and  free  me  from  the  charge  of  presump- 
tion. My  prolegomena  comprise,  under  four 
divisions,  and  in  consonance  with  my  introduc- 
tory remarks  on  the  foundation  of  the  laws  of 
the  universe,  1st.  The  conception  and  limita- 
tion of  physical  cosmography,  as  a  separate  and 
distinct  science. 

2d.  The  objective  contents,  the  comprehen- 
sive empirical  survey,  of  nature  at  large,  in  the 
scientific  form  of  a  general  picture. 

3d.  The  reflex  action  of  nature  upon  the  im- 
agination and  feelings,  as  stimulating  to  its 
study,  through  animated  descriptions  of  remote 
countries,  landscape  poetry  (a  branch  of  mod- 
ern literature),  beautiful  landscape  painting, 
the  cultivation  and  contrasted  grouping  of  ex- 
otic plants,  &c. 

4th.  The  history  of  creation — in  other  words, 
an  account  of  the  gradual  development  and  ex- 
tension of  the  idea  of  the  Cosmos  as  a  natural 
whole. 

The  higher  the  point  of  view  from  which  the 
phenomena  of  nature  are  contemplated,  the 
more  distinctly  must  the  science,  the  founda- 
tions of  which  are  now  to  be  laid,  be  bounded, 
and  marked  off  from  all  allied  departments  of 
natural  knowledge.  Physical  Cosmography  em- 
braces the  description  of  all  that  is  created,  of 
all  that  exists  in  space,  both  natural  things  and 
natural  forces,  as  a  simultaneously  existing  co- 
ordinate whole.  It  divides  itself  for  man,  the 
inhabitant  of  the  earth,  into  two  principal  di- 
visions ;  one  telluric,  another  sidereal  or  uran- 
ological.  To  confirm  the  scientific  independ- 
ence of  physical  cosmography,  and  show  its 
relations  to  other  departments — to  physics  or 
natural  philosophy,  to  natural  history  or  the 
special  description  of  natural  objects,  to  geog- 
aosy  and  comparative  geography,  or  the  de- 
scription of  the  earth — we  shall  first  pause 
over  the  telluric  portion  of  our  subject.  Even 
as  little  as  the  history  of  philosophy  consists  in  a 
crude  arrangement  side  by  side,  or  in  sequence, 
of  the  various  philosophical  opinions  that  have 
been  entertained,  so  little  is  the  telluric  portion 
C 


of  cosmography  any  encyclopaedic  aggregate  of 
the  natural  sciences  enumerated  above.  The 
lines  of  demarcation  between  branches  so  inti- 
mately allied  as  these,  are  the  more  confused 
in  consequence  of  the  custom  which  has  pre- 
vailed for  centuries,  of  designating  by  specific 
titles  certain  groups  of  experimental  knowl- 
edge, which  are  now  too  narrow,  now  too  com- 
prehensive for  the  matters  comprised,  and 
which,  in  times  of  classical  antiquity,  and  in 
the  languages  from  which  they  were  borrowed, 
had  a  totally  different  signification  from  that 
now  attached  to  them.  The  titles  of  particu- 
lar natural  sciences,  such  as  anthropology, 
physiology,  natural  philosophy,  natural  history, 
geognosy,  and  geography,  arose  and  became 
universally  current  before  mankind  had  attain- 
ed to  any  clear  conception  of  the  diversity  of 
objects  embraced  by  these  several  sciences, 
and  the  precise  line  of  demarcation  between 
each — that  is  to  say,  of  the  grounds  of  separa- 
tion themselves.  In  the  language  of  one  of  the 
most  polished  nations  of  Europe,  natural  phi- 
losophy (physics)  is  scarcely  distinguished  from 
medicine  (physic) ;  whilst  technical  chemistry, 
geology,  and  astronomy,  treated  in  an  entirely 
empirical  manner,  are  jumbled  together,  and 
papers  on  all  are  published  under  the  joint  title 
of  Philosophical  Transactions,  by  a  Society 
whose  fame  is  justly  as  wide  as  the  world. 

Alterations  of  old,  often  ill  chosen,  but  gen- 
erally well  understood  names,  for  newer  titles, 
have  been  repeatedly  attempted,  but  always, 
as  yet,  with  indifferent  success,  by  those  who 
have  turned  their  attention  to  the  classification 
of  the  several  departments  of  human  knowl- 
edge, from  the  Margarita  Philosophica  (a  great 
Encyclopaedia)  of  the  Carthusian  monk  Grego- 
ry Reisch(^),  to  Bacon  ;  from  Bacon  to  d'Alera- 
bert,  and,  not  to  forget  the  very  latest  times, 
to  the  acute  geometrician  and  natural  philoso- 
pher, Ampere(=*).  The  unfelicitous  choice  of 
a  fantastical  nomenclature  has  perhaps  been 
more  prejudicial  to  every  attempt  of  the  kind, 
than  the  excessive  number  of  divisions  and 
subdivisions  that  have  been  introduced. 

Physical  cosmography,  whilst  it  embraces 
the  world  "  as  an  object  of  the  external  sen- 
ses," requires,  it  is  true,  the  association  of  gen- 
eral physics  and  natural  history  as  auxiliary 
sciences ;  but  the  consideration  of  corporeal 
things,  under  the  guise  of  a  natural  whole, 
moved  and  actuated  by  inherent  forces,  has  an 
entirely  special  character  as  a  distinct  science. 
Physics  occupies  itself  with  the  general  prop- 
erties of  matter :  it  is  an  abstraction  from  the 
manifestations  of  force  by  matter  ;  and  in  the 
very  place  where  its  first  foundations,  as  a  sci- 
ence, are  laid,  viz.,  in  the  eight  books  of  the 
Physics  of  Aristotle(3),  all  the  phenomena  of 
nature  are  represented  as  vital  manifestations 
of  a  general  cosmic  force.  The  telluric  por- 
tion of  physical  cosmography,  to  which  I  will- 


18 


LIMITATION  AND  TREATMENT 


ingly  concede  the  old  title,  Physical  History 
of  the  Globe,  treats,  among  other  matters,  of 
the  distribution  of  magnetism  over  our  planet, 
with  reference  to  intensity  and  direction  ;  not 
of  the  laws  of  magnetical  attraction  and  repul- 
sion, nor  of  the  means  of  exciting  electro-mag- 
netical  effects,  now  of  a  more  passing,  now  of 
a  more  permanent  character.  Physical  cos- 
mography displays,  in  bold  outlines,  the  parti- 
tionings  of  continents  and  the  distribution  of 
their  masses  in  either  hemisphere — points  that 
influence  climate  and  the  more  important  me- 
teorological processes  in  the  most  remarkable 
manner ;  it  goes  farther — it  indicates  the  pre- 
vailing characters  of  the  several  great  mount- 
ain ranges,  their  extension  in  more  continuous 
and  even  chains,  or  their  connections  in  the 
manner  of  a  grating,  and  their  association  with 
the  several  epochs  and  systems  of  formation  ; 
it  determines  the  mean  height  of  continents 
above  the  present  level  of  the  sea  ;  the  points 
of  the  centres  of  gravity  of  their  volumes  ;  the 
relations  of  the  higher  peaks  of  extensive  chains 
to  their  acclivities,  to  neighbouring  seas,  and 
to  the  mineral  nature  of  their  constituent  rocks ; 
it  informs  us  how  these  mountain  masses,  now 
active  and  moving,  breaking  through  a  super- 
imposed crust,  now  passive  and  moved,  pre- 
sent their  strata  under  every  variety  of  inclina- 
tion— level,  sloping,  perpendicular ;  it  consid- 
ers the  succession  or  isolation  of  volcanoes ; 
the  indications  of  their  manifestations  of  activ- 
ity, the  extent  of  the  circles  they  severally 
shake,  and  which  in  the  course  of  centuries 
enlarge  or  contract.  It  farther  informs  us,  to 
select  a  few  examples  from  the  conflict  of  the 
fluid  with  the  solid,  of  the  points  of  resemblance 
between  all  mighty  streams  in  one  part  or  an- 
other of  their  course :  how  they  are  liable  to 
bifurcate,  either  in  their  superior  or  inferior 
channels ;  how  at  one  time  they  cut  across 
colossal  mountain  chains  at  right  angles,  at  an- 
other, run  in  lines  parallel  to  them,  whether 
this  be  near  the  declension  of  the  chain,  or  at 
some  considerable  distance  from  it,  as  a  con-' 
sequence  of  the  influence  which  an  elevated 
mountain  system  has  exerted  upon  the  surface 
of  entire  districts  of  country,  and  on  the  saline 
bottoms  of  neighbouring  plains.  Only  the  chief 
results  of  comparative  orography  and  hydrog- 
raphy belong  to  the  science  which  I  here  cir- 
cumscribe, not  minute  descriptions  of  mount- 
ain masses  ;  of  volcanoes  that  are  now  active  ; 
of  the  volume  of  waters  of  particular  rivers, 
&c.  :  all  this,  according  to  my  views,  belongs 
to  special  or  descriptive  geography,  and  will  be 
comprised  in  the  notes  which  illustrate  my 
work.  The  enumeration  of  similar,  or  closely- 
allied,  natural  relations,  the  general  survey  of 
terrestrial  phenomena  with  reference  to  their 
distribution  in  space,  or  their  relations  to  par- 
ticular zones  of  the  Earth,  is  not  to  be  con- 
founded with  the  consideration  of  the  individu- 
al things  of  Nature,  to  wit,  terrestrial  substan- 
ces, animated  organisms,  physical  phenomena  ; 
a  consideration  which  would  only  lead  to  a 
systematic  arrangement  of  objects,  according 
to  their  intimate  analogies. 

Special  geographical  descriptions  are,  it  is 
true,  the  most  available  material  for  a  general 
physical  geography  ;  but  the  most  painstaking 
accumulation  of  such  descriptions  would  as  lit- 


tle convey  to  the  mind  the  characteristic  idea 
of  terrestrial  nature  at  large,  as  the  mere  co- 
ordination of  all  the  individual  floras  of  the 
earth  would  give  a  notion  of  the  geography  of 
plants.  It  is  the  business  of  the  combining  in- 
tellect, out  of  the  individualities  of  organic 
forms  (morphology,  the  doctrine  of  the  exter- 
nal forms  of  plants  and  animals),  to  extract 
the  common  in  climatic  distribution ;  to  fix  the 
numerical  laws — the  proportions  in  the  num- 
ber of  certain  forms  of  natural  families,  to  the 
entire  number  of  plants  or  animals  of  the  more 
perfect  types  ;  to  determine  in  what  zone  each 
of  the  principal  forms  attains  its  maximum  in 
point  of  numbers  of  kinds  and  organic  develop- 
ment, and  even  to  show  how  the  impression 
niade  upon  the  mind  by  a  landscape  at  different 
distances  from  the  equator,  in  so  far  as  this  is 
connected  with  the  vegetable  growths  that 
cover  the  surface  of  our  planet,  is  mainly  de- 
pendent on  the  laws  of  vegetable  geography. 

Those  systematically  arranged  catalogues  of 
organic  forms,  which  in  former  times  were 
designated  by  the  somewhat  ostentatious  titles 
of  Systems  of  Nature,  present  a  wonderful 
enchainment  in  reference  to  similarity  of  form 
(structure),  to  the  conception  of  a  gradual  un- 
folding or  evolution  of  leaf  and  calyx  into  col- 
oured blossom  and  fruit,  but  not  any  concate- 
nation with  reference  to  distribution  in  space, 
that  is  to  say,  to  climate,  elevation  above  the 
level  of  the  sea,  and  to  temperature,  to  which 
the  whole  surface  of  the  globe  is  exposed.  The 
highest  aim  of  physical  geography,  however,  as 
already  observed,  is  the  recognition  of  unity  in 
multiplicity,  the  investigation  of  the  Common 
and  Intimately-connected  in  all  terrestrial  phe- 
nomena. Where  individualities  are  indicated, 
no  more  is  done  than  may  help  to  bring  the 
laws  of  organic  arrangement  into  unison  with 
those  of  geographical  distribution.  The  mass 
of  living  forms,  in  this  point  of  view,  appears 
to  be  arranged  rather  according  to  the  zones 
of  the  earth,  or  to  the  course  of  isothermal 
lines,  than  in  conformity  with  internal  rela- 
tionship, or  the  principle  of  gradation  and  indi- 
vidualizing development  of  organs  inherent  in 
the  whole  of  nature.  The  natural  sequence  of 
vegetable  and  animal  forms  will  therefore  be 
here  assumed  from  our  ordinary  descriptive 
botany  and  zoology.  It  is  the  province  of  phys- 
ical geography  to  investigate  the  mysterious 
generical  relations  in  which,  with  an  apparent 
dispersion  of  families  and  species  over  the  sur- 
face of  the  earth,  the  most  dissimilar  forms 
still  stand  to  one  another ;  to  show  how  the 
various  organisms  constitute  a  natural  whole  ; 
how  they  modify  the  atmosphere  by  the  slow 
processes  of  combustion  and  assimilation  that 
go  on  in  their  interior ;  and  how,  influenced 
by  promethean  light  in  their  evolution,  in  their 
very  being,  despite  their  inconsiderable  mass, 
they  act  upon  the  whole  life  of  the  globe. 

The  mode  of  presenting  the  subject  which  I 
here  propose  as  alone  appropriate  to  physieal 
cosmography,  gains  in  simplicity  when  we  ap- 
ply it  to  the  uranological  portion  of  the  Cos- 
mos, to  the  physical  history  of  heavenly  space, 
and  of  the  heavenly  bodies.  If  we  distinguish 
physics,  or  natural  philosophy,  as  used  former- 
ly to  be  done,  but  as  deeper  and  clearer  views 
of  nature  allow  us  no  longer  to  do — physics, 


OF  A  SCIENTIFIC  COSMOGRAPHY. 


19 


or  the  general  consideration  of  matter,  of  force, 
and  of  motion,  from  chemistry,  or  the  consid- 
eration of  the  different  natures  of  matter,  its 
combinations  and  changes  through  admixture, 
not  through  affinities  in  virtue  of  the  simple 
relations  of  mass,  we  then  perceive,  in  the 
telluric  region,  physical  and  chemical  processes 
existing  together.  Besides  that  fundamental 
property  of  all  matter,  attraction  at  a  distance 
(gravitation),  other  forces  affect  us  here  upon 
earth,  which  come  into  operation  at  infinitely 
small  distances,  or  upon  immediate  contact  be- 
tween material  particles(*),  forces  which  are 
designated  chemical  affinities,  and  which,  called 
into  action  variously  by  electricity,  caloric,  and 
even  simple  contact,  are  incessantly  efficient 
in  inorganic  nature,  as  well  as  in  living  organ- 
isms. In  the  celestial  spaces  we  have  as  yet 
no  apprehension  of  any  other  than  physical 
processes,  affections  of  matter  which  depend 
on  mass  alone,  and  which  are  subjected  to  the 
dynamic  laws  of  a  pure  doctrine  of  motion. 
Such  affections  are  regarded  as  independent  of 
all  qualitative  differences — of  heterogeneous- 
ness  or  specific  difference  of  matter. 

The  inhabitants  of  the  earth  are  brought  into 
relation  with  the  matter  dispersed  over  space, 
only  by  the  phenomena  of  light  and  the  influ- 
ence of  general  gravitation  (attraction  accord- 
ing to  mass).  The  influences  of  the  sun  and 
moon  upon  the  periodical  variations  of  terres- 
trial magnetism,  are  still  buried  in  obscurity. 
We  have  no  immediate  knowledge  or  experi- 
ence of  the  qualitative  nature  of  the  matter 
which  circulates  in,  or  perhaps  fills,  the  uni- 
verse, unless,  perchance,  it  be  through  the  fall 
of  aerolites,  if  these  heated  masses,  involved 
in  vapour,  be  assumed  as  constituting  small 
planetary  bodies  which  have  come  within  the 
sphere  of  the  earth's  attraction  in  their  course 
through  space ;  an  assumption  which  the  di- 
rection and  extraordinary  centrifugal  force  of 
the  bodies  in  question  appears  to  render  proba- 
ble. The  familiar  aspect  of  their  constituent 
elements,  and  the  identity  in  nature  of  these 
with  such  as  we  have  in  abundance  among  the 
mineral  masses  of  the  earth,  are  very  striking. 
They  may  serve,  on  analogical  grounds,  to  lead 
us  to  conclusions  in  regard  to  the  nature  of 
such  planets  as  belong  to  the  same  group,  and 
have  been  formed,  under  the  dominion  of  one 
central  body,  by  precipitation  from  revolving 
rings  of  vaporous  matter.  Bessel's  pendulum- 
experiments,  which  bear  the  impress  of  such 
accuracy  as  has  never  yet  been  attained,  have 
given  a  renewed  faith  in  the  truth  of  the  New- 
tonian axiom,  that  bodies  of  the  most  dissimi- 
lar constitution— water,  gold,  quartz,  granular 
limestone,  aerolites — experience  a  perfectly 
similar  acceleration  of  motion  through  the  at- 
traction of  the  earth.  Many  purely  astronom- 
ical results,  indeed,  for  example  the  almost 
equal  mass  of  Jupiter,  in  consequence  of  the 
influence  of  the  planet  on  his  satellites,  on 
Encke's  comet,  on  the  small  planets  Vesta, 
Juno,  Ceres,  and  Pallas,  assure  us  that  every 
where  it  is  the  quantity  of  matter  alone  which 
influences  its  power  of  attraction(5). 

This  exclusion  of  every  appreciable  circum- 
stance referrible  to  diversity  of  material,  sim- 
plifies the  mechanism  of  the  heavens  in  a  re- 
markable manner ;  it  brings  the  infinite  realms 


of  space  under  the  sole  dominion  of  the  laws 
of  motion;  and  the  astrognostic  portion  of 
physical  cosmography  draws  from  established 
theoretical  astronomy,  in  the  same  way  as  the 
terrestrial  portion  draws  from  physics,  chem- 
istry, and  organic  morphology.  The  depart- 
ments of  science  just  mentioned,  indeed,  em- 
brace phenomena  so  intricate,  and  at  times  so 
opposite  to  mathematical  views,  that  the  ter- 
restrial portion  of  the  doctrine  of  the  Cosmos 
cannot  boast  of  the  same  certainty  and  simpli- 
city of  treatment  as  the  astronomical  portion. 
In  the  distinction  now  indicated  lies  undoubt- 
edly the  reason  wherefore,  in  the  earlier  peri- 
ods of  the  Greek  civilization,  the  Pythagorean 
philosophy  of  nature  was  rather  directed  to  the 
heavens  than  to  the  earth ;  wherefore  it  be- 
came fruitful,  with  reference  to  our  solar  sys- 
tem, in  a  much  higher  degree,  through  Philo- 
laus,  and,  in  later  times,  through  Aristarchus 
of  Samos,  and  Seleucus  the  Erythrean,  than  the 
Ionic  natural  philosophy  could  prove  in  regard 
to  the  physics  of  our  globe.  More  indifferent 
as  to  the  specific  nature  of  that  which  filled 
space,  as  to  qualitative  differences  of  matter, 
the  forces  of  the  Italic  school  were  directed 
with  Doric  earnest  upon  regulated  formations,  '  . 
on  shape,  on  form  and  measure  alone(®) ;  whilst  .1^ 
the  Ionic  physiologists  occupied  themselves 
especially  with  the  consideration  of  species  of 
matter,  with  their  supposed  transmutations  and 
generic  relations.  It  was  reserved  for  the  pow- 
erful, truly  philosophic,  and,  at  the  same  time, 
thoroughly  practical  mind  of  Aristotle,  to  plunge 
with  equal  delight  into  the  world  of  abstraction, 
and  into  the  measureless  abundance  of  material 
diversity  in  organic  forms. 

Several,  and  these  very  excellent  works  upon 
physical  geography,  comprise  an  astronomical 
section  in  their  introduction,  in  which  the  earth 
is  first  considered  in  its  planetary  dependence, 
or  in  its  relations  to  the  rest  of  the  solar  sys- 
tem. This  plan  is  the  very  opposite  of  that 
which  I  have  chalked" out  for  myself.  In  a  sys- 
tem of  cosmography,  the  astronomical  portion, 
which  Kant  entitled  the  Natural  history  of  the 
heavens,  must  not  appear  as  subordinate  to  the 
telluric  portion.  In  the  Cosmos,  as  the  old 
Copernican  philosopher,  Aristarchus  of  Samos, 
said,  the  sun  with  his  attendants  is  a  star 
amongst  innumerable  stars.  A  general  survey 
of  creation  must  consequently  begin  with  the 
heavenly  bodies  that  occupy  space,  with  a 
graphic  delineation,  a  kind  of  map  of  the  celes- 
tial universe,  such  as  the  bold  hand  of  the  elder 
Herschel  first  ventured  to  design.  If  we  see 
that,  despite  the  relative  insignificance  of  our 
planet,  the  terrestrial  portion  still  occupies  the 
largest  space  in  the  history  of  the  universe,  and 
is  most  fully  handled,  this  only  happens  in  re- 
spect of  the  unequal  mass  of  that  which  is 
Known  to  the  inequality  of  that  which  is  Em- 
pirically accessible.  This  subordination  of  the 
uranological  portion  we  already  find  in  the 
great  geographer,  Bernhard  Varenius,  in  the 
middle  of  the  17th  century(0.  He  distinguish- 
es with  much  acumen  between  the  General  and 
Special  description  of  the  earth,  and  subdivides 
the  former,  into  the  absolutely  terrestrial  and 
the  planetary,  according  as  the  relations  of  the 
surface  of  the  earth  in  different  zones,  or  the 
sol-lunar  life  of  the  earth — the  relations  of  our 


20 


LIMITATION  AND  TREATMENT 


planet  to  the  sun  and  moon — are  considered. 
It  is  a  great  and  enduring  honour  to  Varenius, 
that  the  reahzation  of  this  plan  of  a  General 
and  of  a  Comparative  Geography  attracted 
Newton's  attention  in  a  very  decided  manner  ; 
but  owing  to  the  imperfect  state  of  the  acces- 
sory sciences  from  which  Varenius  drew,  the 
way  in  which  the  idea  could  be  carried  out  was 
not  in  accordance  with  the  grandeur  of  the  con- 
ception. It  was  reserved  for  our  own  times  to 
see  comparative  geography,  in  the  widest  sense 
of  the  expression,  even  in  its  reflex  on  the  his- 
tory of  mankind — the  influence  which  the  fig- 
ure of  continents  has  had  on  the  course  of  the 
great  migrations  of  the  human  family,  and  the 
progress  of  civilization,  worked  out  in  the  most 
masterly  manner(^). 

The  enumeration  of  the  various  rays  which 
unite  as  in  a  focus  in  the  natural  sciences  con- 
sidered as  a  whole,  may  serve  as  an  apology 
for  the  title  of  the  work  which  I  venture  to  pro- 
duce in  the  late  evening  of  my  life.  This  title 
is  perhaps  even  bolder  than  the  undertaking  it- 
self, considering  the  limits  which  I  have  pre- 
scribed myself  In  the  special  departments,  I 
had  hitherto  avoided  as  much  as  possible  the 
use  of  new  names  for  the  indication  of  new 
conceptions.  Where  I  attempted  any  exten- 
sion of  our  nomenclature,  it  was  always  con- 
fined to  individual  objects  in  zoology  and  bota- 
ny. The  term.  Physical  Cosmography,  which 
I  here  employ,  is  imitated  from  the  phrase, 
Physical  Geography,  which  has  long  been  fa- 
miliar to  all.  The  great  extent  of  the  subject 
embraced,  the  purpose  of  surveying  nature  at 
large,  from  the  remote  nebulous  specks  in  the 
heavens,  to  the  climatic  distribution  of  the  or- 
ganic tissues  that  colour  the  face  of  our  rocks, 
make  the  introduction  of  a  new  term  necessa- 
ry. And  however  completely  our  old  and  usual 
terms  earth,  and  world,  blend  together,  as  we 
see  them  in  the  familiar  phrases  of,  a  voyage 
round  the  world,  a  map  of  the  world,  the  new 
world,  &c.,  this  is  a  mere  consequence  of  the 
former  more  limited  knowledge  of  mankind ; 
the  scientific  distinction  between  the  world,  or 
universe  at  large,  and  the  earth  we  inhabit,  is 
now  felt  to  be  a  matter  of  common  necessity. 
The  grander  and  more  correct  expressions, 

UNIVERSE,    FABRIC    OF   THE    UNIVERSE,    CREATION, 

and  NATURE,*  employed  to  designate  the  con- 
ception and  origin  of  all  matter,  terrestrial  as 
well  as  that  of  the  farthest  stars,  seem  to  ap- 
prove the  propriety  of  this  distinction.  To 
make  this  more  definite,  I  might  say  more  sol- 
emn and  impressive,  and  also  to  recur  to  the 
antique  name,  I  have  placed  the  word  Cosmos 
(KOSMOS)  at  the  head  of  my  work  ;  this  term, 
in  the  Homeric  times,  having  been  used  to  in- 
dicate beauty  and  order,  but  by  and  by  employ- 
ed as  a  philosophical  expression  to  indicate  the 
harmony  or  arrangement  of  the  world,  even  of 
the  entire  mass  of  matter  filling  space,  of  the 
universe  at  large. 

The  difliculty  of  distinguishing  the  normal— 
the  regular  and  legitimate— amidst  the  cease- 
less changes  of  earthly  phenomena,  appears  at 
an  early  period  to  have  directed  the  mind  of 
man,  in  an  especial  manner,  to  the  uniform  and 

*  Weltgebftude,  Weltkorper,  Weltschopfung,  Weltraum, 
German ;  literally  Worldfabric,  Worldbodies,  Worldcrea- 
tioD,  Worldspace. 


harmonious  movements  of  the  heavenly  bodies. 
According  to  Philolaus,  and  the  concurring  tes- 
timony of  the  whole  of  antiquity ('),  Pythagoras 
was  the  first  who  employed  the  word  Cosmos 
as  synonymous  with  creation,  with  the  order 
and  arrangement  of  the  earth  and  heavenly 
bodies.  From  the  Italic  philosophical  school, 
the  word  passed  into  the  language  of  the  poets 
of  nature,  Parmenides  and  Empedocles  ;  and  by 
and  by  it  was  adopted  by  the  prose  writers.  It 
is  beyond  my  purpose  to  expatiate  in  this  place 
on  the  various  particular  applications  of  the 
term,  according  to  Pythagorean  views — now  to 
the  planets  that  revolve  around  the  focus  of  the 
world,  now  to  groups  of  stars  in  the  firmament ; 
or  to  explain  that  Philolaus,  on  one  occasion, 
distinguishes  between  Olympus,  Kosmos,  and 
Uranus.  In  my  plan  of  a  cosmography,  as  this 
was  understood  in  times  posterior  to  Pythago- 
ras, and  as  the  term  is  used  by  the  unknown 
author  of  the  book,  De  Mundo,  which  was  so 
long  ascribed  to  Aristotle,  Cosmos  is  used  to 
designate  the  conception  of  the  heavens  and 
earth — of  the  whole  of  the  material  universe. 
The  Romans,  in  the  spirit  of  imitation,  and 
when  they  came  to  pay  a  tardy  attention  to 
philosophy,  adopted  the  word  Mundus,  which 
originally  signified  ornament,  never  order,  for 
the  designation  of  the  universe.  The  intro- 
duction of  the  technical  term  into  the  Latin 
tongue,  the  literal  translation  of  the  Greek  Kos- 
mos, used  in  a  double  sense,  is  probably  to  be 
ascribed  to  Ennius(^°),  a  disciple  of  the  Italic 
school,  and  the  translator  of  the  Pythagorean 
philosophical  speculations  of  Epicharmus,  or  of 
one  of  his  imitators. 

As  a  physical  history  of  the  world,  in  the  wi- 
dest sense  of  the  word,  were  the  materials  ac- 
cessible for  such  an  undertaking,  would  pass  in 
review  the  changes  which  the  Cosmos  under- 
goes in  the  lapse  of  time,  from  the  new  stars 
which  suddenly  make  their  appearance  in  the 
heavens,  and  the  nebulae  which  either  dissolve 
.and  disappear,  or  become  condensed  in  their 
centres,  to  the  most  insignificant  vegetable  tis- 
sue that  first  covered  the  cold  crust  of  the  earth, 
or  that  gradually  and  progressively  overspreads 
the  coral  reef  which  rises  from  the  bosom  of 
the  ocean,  so  would  a  physical  description  of 
the  world,  on  the  other  hand,  portray  the  co- 
existent in  space,  the  simultaneous  agency  of 
the  natural  forces,  and  of  the  concrete  forms 
that  are  the  product  of  these  forces.  The  Ex- 
isting, however,  in  our  conception  of  nature,  is 
not  to  be  absolutely  distinguished  or  separated 
from  the  Coining  into  Existence  ;  for  it  is  not 
the  organic  alone  that  is  to  be  conceived  as 
ceaselessly  involved  in  coming  into  being  and 
ceasing  to  be ;  the  whole  life  of  the  globe,  in 
each  stage  of  its  existence,  refers  us  to  earlier 
conditions  that  have  been  successively  passed 
through.  The  various  superimposed  strata,  of 
which  the  outer  crust  of  our  earth  consists  in 
principal  part,  inclose  the  remains  of  a  creation 
that  has  almost  entirely  disappeared  ;  they  give 
us  to  wit  •f  a  series  of  formations,  which,  in 
groups,  have  successively  supplanted  one  an- 
other ;  they  disclose  to  the  eye  of  the  observer 
the  aggregate  faunas  and  floras  of  bygone  mil- 
lenniums. In  this  sense,  the  Description  of 
Nature,  and  the  History  of  Nature,  are  not  en- 
tirely to  be  dissevered.     The  geologist  cannot 


OF  A  SCIENTIFIC  COSMOGRAPHY. 


31 


apprehend  the  present  without  understanding 
the  past.  Each  penetrates  the  other,  and  blends 
in  a  natural  picture  of  the  globe  ;  just  as  in  the 
vast  domain  of  language,  the  etymologist  finds 
reflected  in  various  states  of  grammatical  forms, 
in  their  rise  and  progressive  development,  the 
whole  of  the  present  in  the  past.  But  this  re- 
flection of  what  has  been,  is  by  so  much  the 
clearer  in  the  material  world,  as  we  now  see 
several  products  forming  themselves  under  our 
eyes.  Among  mountain  masses,  to  choose  an 
example  from  geology,  trachytic  cones,  basalt, 
layers  of  pumice  and  amygdaloidal  scoriae,  en- 
liven the  landscape  in  a  remarkable  manner. 
They  work  upon  our  imagination  like  tales  from 
antiquity  ;  their  form  is  their  history. 

Existence  in  its  whole  extent  and  intimacy 
is  first  completely  known  as  a  something  that 
has  become.  To  this  original  blending  of  con- 
ceptions, classic  antiquity  bears  witness  in  the 
use  of  the  word  History,  both  by  Greece  and 
Rome.  If  not  included  in  the  definition  which 
Verrius  Flaccus(^^)  gives  of  the  term.  History 
is  used  in  the  zoological  writings  of  Aristotle 
to  signify  a  narrative  of  things  investigated,  of 
matters  recognized  by  the  senses.  The  de- 
scription of  the  World  of  the  elder  Pliny  bears 
the  title  Historia  Natural  is ;  in  the  letters  of 
the  nephew,  it  is  more  worthily  designated  "  a 
History  of  Nature."  In  the  times  of  classical 
antiquity,  the  early  historian  makes  little  dis- 
tinction between  descriptions  of  countries  and 
the  narrative  of  events  of  which  these  countries 
were  the  theatre.  Physical  geography  and  his- 
tory continued  long  to  present  themselves  pleas- 
antly mingled  together,  until  increasing  politi- 
cal interests,  and  deeper  movements  in  civic  ex- 
istence, pushed  aside  the  former  element,  which 
then  took  its  place  as  a  separate  department  of 
human  science. 

To  embrace  the  multiplicity  of  the  phenom- 
ena of  the  Cosmos  in  unity  of  thought,  in  the 
form  of  a  purely  rational  series,  is  not,  as  I 
conceive,  possible  in  the  present  state  of  our 
empirical  knowledge.  The  sciences  of  experi- 
ment are  never  complete  ;  the  realm  of  the  im- 
pressions of  sense  is  not  to  be  exhausted  ;  no 
generation  of  men  will  ever  have  it  in  their 
power  to  boast,  that  they  have  surveyed  the 
whole  of  the  world  of  phenomena.  It  is  only 
where  phenomena  can  be  grouped,  and  separ- 
ated from  one  another,  that  we  recognize  in 
the  individual  groups  the  empire  and  agency  of 
grand  and  simple  natural  laws.  The  more  the 
physical  sciences  improve,  the  wider  also  does 
the  boundary  of  this  empire  extend.  Brilliant 
instances  of  the  truth  of  this  have  been  afford- 
ed by  recent  views  of  the  processes  going  on 
in  the  solid  crust  of  the  globe,  as  well  as  in  the 
atmosphere,  which  depend  on  electro-magnetic 
forces,  on  radiant  heat,  and  the  propagation 
of  pulses  of  light ;  brilliant  examples,  too,  are 
supplied  by  the  late  insight  gained  into  the  laws 
of  organic  evolution,  where  all  that  is  to  be,  is 
indjcated  beforehand,  where  the  continuous 
growth  and  progressive  development  of  cells 
give  rise  to  all  the  varied  tissues  of  plants  and 
animals.  In  this  generalization  of  laws,  which 
at  first  seemed  only  to  comprise  much  narrow- 
er circles,  mere  isolated  groups  of  phenomena, 
there  are  numerous  grades.  The  empire  of 
recognized  laws  gains  in  extent,  that  of  ideal 


connection  in  clearness,  so  long  as  inquiries 
are  pursued  in  what  may  be  called  analogous 
and  allied  masses.  But  where  our  dynamic 
views,  which  are  based  on  figurative  atomic 
premises,  no  longer  suffice  us,  because  the  spe- 
cific nature  of  matter,  and  its  heterogeneous- 
ness  come  into  play,  we  find  ourselves  striking 
suddenly  upon  reefs  that  rise  from  fathomless 
depths,  when  we  strive  after  unity  of  compre- 
hension. Here  the  operation  of  a  new  kind  of 
force  is  unfolded.  The  law  of  definite  propor- 
tions, or  numerical  relations,  which  the  genius 
of  modern  chemistry  has  recognized,  and  has 
applied  so  happily,  so  brilliantly,  but  still  under 
an  antique  vesture,  in  the  symbols  of  atomic 
representative  expressions,  has  yet  remained 
isolated,  has  not  been  brought  under  the  do- 
minion of  the  laws  of  pure  dynamics. 

The  individualities  to  which  all  the  imme- 
diate perceptions  of  the  mind  are  limited,  can 
be  logically  arranged  into  classes  and  families. 
Such  arrangements  lead,  as  I  have  already  had 
occasion  to  remark,  in  so  far  as  Nature  is  con- 
cerned, to  the  high-sounding  titles  of  Systems 
of  Nature.  They  facilitate  the  study,  it  is  true, 
of  organic  forms  and  their  linear  enchainment 
with  one  another  ;  but  as  catalogues,  they  pre- 
sent a  mere  formal  enumeration  ;  they  intro- 
duce more  of  unity  into  the  exposition  than 
into  the  knowledge  itself  As  there  are  de- 
grees in  the  generalization  of  natural  laws, 
according  as  they  comprise  larger  or  smaller 
groups  of  phenomena,  wider  or  narrower  cir- 
cles of  organic  forms  and  members,  so  are 
there  also  grades  in  empirical  inquiry.  It  be- 
gins with  isolated  views,  which  are  separated 
and  ordered  according  to  their  kinds.  From 
observation  it  goes  on  to  experiment,  to  evo- 
cation of  phenomena  under  determinate  con- 
ditions, according  to  guiding  hypotheses  ;  in 
other  words,  according  to  the  presentiment  of 
the  intimate  connection  of  natural  things  and 
natural  forces.  What  is  attained  through  ob- 
servation and  experiment,  leads,  on  grounds 
of  analogy  and  induction,  to  the  knowledge  of 
empirical  laws.  These  are  the  phases  through 
which  observing  intellect  must  pass,  and  which 
indicate,  at  the  same  time,  particular  epochs 
in  the  history  of  natural  science  among  men. 

Two  forms  of  abstraction  dominate  the  en- 
tire mass  of  our  knowledge :  one,  quantita- 
tive, indicative  of  relationship  according  to 
number  and  volume ;  the  other,  qualitative, 
relationship  in  reference  to  material  constitu- 
tion. The  former,  and  more  accessible  form, 
belongs  to  the  mathematical,  the  second  to  the 
chemical  sciences.  In  order  to  subject  phe- 
nomena to  calculation,  matter  is  assumed  as 
composed  of  molecules,  or  atoms  ;  the  number, 
form,  position,  and  polarity  of  which  give  oc- 
casion to  phenomena.  All  myths  about  im- 
ponderable matters  and  special  vital  forces  in- 
herent in  organized  beings,  only  render  views 
of  nature  perplexed  and  indistinct.  Under  great 
variety  of  conditions  and  forms  of  apprehen- 
sion, the  heavy  burthen  of  our  accumulated, 
and  still  accumulating  knowledge,  is  moved 
lazily  and  reluctantly.  Reason,  boldly  and  with 
increasing  success,  now  seeks  to  break  down 
the  ancient  forms,  by  means  of  which,  as  with 
mechanical  contrivances  and  symbols,  man  has 
still  been  wont  to  strive  to  obtain  mastery  over 
rebellious  matter. 


23 


LIMITATION  AND  TREATMENT 


"We  are  still  far  from  the  time  when  it  will 
be  possible  to  concentrate  all  perceptions  of 
sense,  into  unity  of  conception  of  Nature.  It 
may  even  be  said  to  be  problematical  whether 
this  time  will  ever  come.  The  complicated 
character  of  the  problem,  and  the  infinity  of 
the  universe,  seem  almost  to  render  vain  the 
hope  that  it  ever  will.  But  though  the  com- 
plete solution  of  the  problem  may  remain  un- 
attainable, its  partial  solution  may  still  be  an- 
ticipated ;  the  effort,  indeed,  to  understand  the 
phenomena  of  the  universe  is  still  the  highest, 
as  it  is  the  eternal  goal  of  all  natural  investiga- 
tion. Faithful  to  the  character  of  my  early 
writings,  as  to  the  nature  of  my  occupations, 
which  have  still  been  devoted  to  experiments, 
to  measurements,  to  the  minute  examination 
of  facts,  I  limit  myself  in  my  present  underta- 
king to  the  empirical,  or  experimental  method. 
It  supplies  the  only  ground  upon  which  I  feel 
that  I  can  move  with  less  of  uncertainty.  But 
this  treatment  of  an  empirical  science,  or  rather 
of  an  aggregate  of  empirical  knowledge,  does 
not  preclude  arrangement  of  the  conclusions 
come  to,  in  harmony  with  leading  ideas,  the 
generalization  of  the  special,  the  ceaseless 
search  after  empirical  natural  laws. 

Knowledge  acquired  under  the  guidance  of 
thought,  the  attainment  of  a  rational  compre- 
hension of  the  universe,  holds  out  yet  a  higher 
object.  I  am  far  from  blaming  efforts  in  which 
I  have  myself  made  no  trial  of  my  strength, 
because  their  fruits  still  remain  subject  of 
doubt.  Greatly  misunderstood,  and  much 
against  the  views  and  the  counsel  of  the  pow- 
erful thinkers  whom  these,  the  special  matters 
that  engaged  antiquity,  have  again  attracted, 
systems  of  what  was  called  the  Philosophy  of 
Nature,  threatened,  for  a  time,  to  lead  men 
away  from  the  study  of  the  mathematical  and 
physical  sciences,  so  important  in  themselves, 
so  intimately  connected  with  the  material  wel- 
fare of  mankind.  The  intoxicating  delirium  of 
possession  obtained  by  toil,  a  peculiarly  adven- 
turously symbolical  language,  a  schematic  dis- 
cipline, narrower  than  ever  the  middle  age  of 
humanity  forced  itself  into,  have,  in  the  youth- 
ful misapplication  of  noble  powers,  been  the 
features  that  distinguished  the  brilliant,  but 
short-lived  Saturnalia  of  this  purely  ideal  nat- 
ural science — I  repeat  the  expression,  misap- 
plication of  powers  ;  for  the  sober  spirits  dedi- 
cated at  once  to  philosophy  and  to  observation, 
continued  strangers  to  these  excesses.  The 
conception  of  Experimental  Science  in  general, 
and  of  a  Philosophy  of  Nature  complete  in  all 
its  parts,  if  such  perfection  can  ever  be  obtain- 
ed, cannot  stand  in  contradiction  or  opposition 
to  one  another,  if  the  Philosophy  of  Nature, 
true  to  its  promise,  be  the  rational  comprehen- 
sion of  the  phenomena  of  the  universe.  Where 
contradiction  shows  itself,  the  blame  lies  in 
the  hoUowness  of  the  speculation,  or  in  the 
arrogance  of  empiricism,  which  thinks  it  gains 
more  from  experience  than  experience  war- 
rants 

And  here  the  realm  of  the  Spiritual  might 
be  opposed  to  the  Natural  ;  as  if  the  spiritual, 
too,  were  not  contained  within  the  concept  of 
nature  as  a  whole  !  Or  Art  may  be  opposed 
to  Nature,  by  Art  being  implied  something 
more  than  the  idea  of  the  spiritual  faculty  of 


producing  which  is  inherent  in  man.  Yet  these 
opposites  must  not  lead  to  such  a  separation  of 
the  physical  from  the  intellectual  as  would 
make  the  physics  of  the  universe  sink  down 
into  a  mere  heap  of  empirically  collected  indi- 
vidualities. Science  begins  at  the  point  where 
mind  dominates  matter,  where  the  attempt  is 
made  to  subject  the  mass  of  experience  to  the 
scrutiny  of  reason ;  science  is  mind  brought 
into  connection  with  nature.  The  external 
world  exists  to  us  only  when  we  receive  it  into 
our  interior,  when  it  has  fashioned  itself  with- 
in us  into  a  natural  perception.  Mysteriously 
indivisible,  as  are  mind  and  language,  as  are 
thought  and  the  fructifying  word,  even  so  and 
to  us  all  consciously,  does  the  external  world 
blend  with  the  interior  in  man,  with  thought 
and  with  emotion.  "External  phenomena," 
says  Hegel,  in  his  Philosophy  of  History,  "  are 
thus  translated  into  internal  conceptions. "  The 
external  or  objective  world,  conceived  by  us, 
reflected  in  us,  is  then  subjected  to  the  eternal, 
necessary,  and  all-influencing  forms  of  our  spir- 
itual existence.  Our  intellectual  activity  then 
exercises  itself  upon  the  material  that  has  been 
taken  in  through  perceptions  of  sense.  There 
is,  therefore,  a  tendency  to  philosophical  ideas 
even  in  the  infancy  of  human  society,  in  the 
simplest  views  that  can  ever  be  taken  of  na- 
ture. This  impulse  is  various,  more  or  less 
lively,  according  to  the  temper  of  the  mind,  to 
national  peculiarity,  and  to  the  state  of  intel- 
lectual culture  among  communities.  The  work 
of  the  mind  begins  so  soon  as  thought,  impelled 
by  internal  necessity,  takes  up  the  material  of 
sensible  impressions. 

History  has  preserved  us  records  of  the  oft 
and  variously  repeated  attempt  to  comprehend 
the  world  of  physical  phenomena  in  its  multi- 
plicity, to  get  at  the  knowledge  of  a  peculiar 
penetrating,  moving,  compounding,  and  decom- 
pounding power  pervading  the  universe.  These, 
attempts,  in  classical  times,  constituted  the 
physiologies  and  doctrines  of  the  primeval  mat- 
ter of  the  Ionic  school,  in  which,  by  the  side 
of  a  poorly  arranged  empiricism,  a  scanty  dis- 
play of  facts,  ideal  efforts,  or  efforts  to  explain 
nature  upon  grounds  of  pure  reason,  prevailed. 
But  the  more  the  material  of  certain  empirical 
knowledge  accumulated,  under  the  influence  of 
a  brilliant  extension  of  all  the  natural  sciences, 
the  more  did  the  impulse  cool  which  led  men  to 
seek  to  comprehend  the  essence  of  phenomena, 
and  to  discover  their  unity  as  a  natural  whole, 
by  the  construction  of  systems  prompted  by 
pure  reason.  In  times  that  have  but  recently 
gone  by,  the  mathematical  portion  of  natural 
philosophy  has  had  to  rejoice  in  a  great  and  no- 
ble development.  The  methods  and  the  instru- 
ment (Analysis),  have  advanced  towards  per- 
fection simultaneously.  And  what  was  elicited 
in  such  a  variety  of  ways — by  a  judicious  appli- 
cation of  atomical  premises,  by  a  more  general 
and  more  immediate  contact  with  nature,  by 
the  invention  and  improvement  of  new  instru- 
ments, is  now,  as  of  old,  the  common  inherit- 
ance of  mankind,  and  ought  not  to  be  lost  to 
the  freest  operations  of  philosophy,  however 
changing  in  her  forms.  Hitherto,  indeed,  the 
inviolability  of  the  material  has  run  certain 
risks  in  the  process  of  reconstruction ;  and  in 
the  ceaseless  change  of  idealistic  views,  it  i9 


OF  A  SCIENTIFIC  COSMOGRAPHY. 


23 


little  to  be  wondered  at,  if,  as  finely  observed 
by  Bruno("),  "  Many  regard  philosophy  as  sus- 
ceptible of  no  more  than  a  sort  of  meteoric  ex- 
istence, so  that  even  the  larger  and  more  re- 
markable forms  in  which  she  has  revealed  her- 
self to  mankind  share  the  fate  of  comets,  which 
are  not  regarded  as  belonging  to  the  imperish- 
able and  eternal  works  of  nature,  but  are  mere- 
ly reckoned  among  the  number  of  fiery  va- 
pours." 

Misuse  or  misdirection  of  the  mental  ener- 
gies, however,  must  not  lead  to  any  conclusions 
tending  to  degrade  intellect ;  as  if  the  world  of 
thought  were,  from  its  very  nature,  the  realm 
of  phantasms  and  deceptions ;  as  if  the  pre- 


cious stores  of  empirical  knowledge,  which 
have  been  accumulating  for  centuries,  were 
threatened  by  philosophy  as  by  some  hostile 
power !  It  becomes  not  the  spirit  of  these 
times  to  reject,  as  groundless  hypothesis,  eve- 
ry generalization  of  ideas,  every  attempt,  based 
upon  analogy  and  induction,  to  investigate  the 
concatenation  of  the  phenomena  of  nature  ; 
and,  among  the  noble  faculties  with  which  na- 
ture has  so  wonderfully  furnished  man,  to  con- 
demn at  one  time  reason,  inquiring,  searching 
every  where  for  causal  connections ;  at  an- 
other imagination,  the  active,  the  exciting, 
the  indispensable  to  all  invention,  to  all  discoT- 
ery. 


NOTES  TO  PRECEDING  SECTION. 


1  (p.  J».)— The  "  Margarita  philosophica"  of  the  Carthu- 
■i»n  prior  of  Freiburg,  Gregorius  Reisch,  first  appeared  un- 
der the  title  of  "  Aepitome  omnis  Philosophic,  alias  Mar- 
garita philosophica  tractans  <3e  omni  genere  scibili,"  vide 
the  Heidelberg  edition  of  1486,  and  that  of  Strasburg  of 
1504.  In  the  Freiburg  edition  of  that  year,  and  in  the 
twelve  following  editions,  which  appeared  in  the  short  in- 
terval till  1535,  the  first  part  of  the  title  was  omitted.  This 
work  exercised  a  great  influence  on  the  diffusion  of  mathe- 
matical and  physical  knowledge  at  the  beginning  of  the  16th 
century  ;  and  Chasles,  the  learned  author  of  the  "  Aperfu 
historique  des  m^thodes  en  g6om6trie"  (1837),  has  shown 
How  important  is  Reisch's  Encyclopedia  for  the  mathemat- 
ical history  of  the  middle  ages.  I  have  endeavoured,  by 
means  of  a  passage  of  the  "  Margarita  philosophica,"  and 
which  only  occurs  in  the  edition  of  1513,  to  unravel  the  im- 
portant relations  of  Hylacomilus  (Martin  Waldseemiiller) 
the  geographer  of  St.  Di6,  who  first  (1507)  named  the  New 
Continent  America,  with  Amerigo  Vespucci,  with  Ren6 
King  of  Jerusalem  and  Duke  of  Lorraine,  and  with  the  cel- 
ebrated editions  of  Ptolemy  of  1513  and  1522.  Vide  my 
'*  Examen  critique  de  la  g6ographie  du  nouveau  Continent,  et 
des  progres  de  I'astronomie  nautique  aux  15e  et  16e  siecles," 
torn.  iv.  pp.  99—125. 

3  (p.  17.)— Ampere,  "  Essai  sur  la  Phil,  des  Sciences," 
1834,  p.  25.  Whewell's  Inductive  Philos.,  vol.  ii.  p.  277 ; 
park's  Pantology,  p.  87. 

3  (p.  17.) — All  changes  of  state  in  the  material  world  are 
reduced  to  motions.  Aristot.  Phys.  ausc.  iii.  1  and  4,  pp. 
200—201  ;  Bekker,  viii.  1,  8,  and  9,  pp.  250,  262,  265;  De 
gener.  et  corr.  ii.  10,  p.  336  ;  Pseudo- Aristot.  de  mundo,  cap. 
vi.  p.  398. 

•♦  (p.  19.) — Respecting  the  question  raised  by  Newton  of 
the  difference  between  mass-attraction  and  that  otf  mole- 
cules, vide  Laplace's  "  Exposit.  du  syst.  du  monde,"  p.  384, 
and  in  the  *'  Supplement  au  livre  x.  de  la  m^canique  eel." 
pp.  3,  4. — (Kant's  Metaphysical  Elements  of  Natural  Phi- 
losophy, in  collective  Works,  1839,  vol.  v.  p.  309  ;  Peclet's 
Physique,  1838,  torn.  i.  pp.  59—63.) 

5  (19.) — Poisson,  in  Conn,  des  terns  pour  I'ann^e  1836, 
pp.  64 — 66  ;  Bessel,  in  Poggendorff's  Annalen  der  Physik, 
vol.  XXV.  p.  417  ;  Encke,  in  Berlin  Academy's  Transactions, 
1826,  p.  257:  Mitscherlich's  Man.  of  Chemistry,  1837,  vol. 
i.  p.  353. 

6  (p.  19.) — Compare  Otfried  Miiller's  Dorians,  vol.  i.  p. 
365. 

7  (p.  19.) — "  Geographia  generalis  in  qua  affectiones  gen- 
erates telluris  explicantur."  The  oldest  Amsterdam  edition 
(Elzevir)  is  of  1650 ;  the  second  of  1672,  and  the  third  of 
1681,  were  edited  by  Newton.  This  all-important  work  of 
Varenius  is  a  Physical  Geography  in  its  proper  sense. 
Since  the  excellent  description  of  the  New  Continent  by 
the  Jesuit,  Joseph  da  Acosta  (Historia  natural  de  las  Indias, 
1590),  never  had  the  telluric  phenomena  been  so  generally 
contemplated.  Acosta  is  richer  in  individual  observations  ; 
Varenius  embraces  a  greater  circle  of  ideas— his  residence 
in  Holland,  then  the  centre  of  the  Commerce  of  the  world, 
having  connected  him  with  many  intelligent  travellers. 
"  Generalis  sive  universalis  Geographia  dicitur,  qua  tellu- 
rem  in  genere  considerat  atque  affectiones  explicat,  non 
habita  particularium  regionum  ratione."  Varenius's  Uni- 
versal Geography  {Pars  absoluta,  ca,p.  i. — xxii.)  is  altogeth- 
er a  comparative  one,  although  the  author  uses  the  term 
Geographia  comparativa  (cap.  xxxiii.— xl.)  in  a  much  more 
restricted  meaning.  The  remarkable  parts  are  the  enu- 
meration of  mountain-systems  and  reflections,  or  the  rela- 
tions of  their  directions  with  the  whole  continents  (pp.  66- 
76,  ed.  Cantab.  1681) ;  the  list  of  the  active  and  extinct 
volcanoes  ;  the  conjunction  of  results  on  the  division  of  isl- 
ands and  island  groups  (p.  220) ;  on  the  depth  of  the  ocean 
compared  with  the  height  of  the  coast  (p.  103)  ;  on  the 
equal  levels  of  the  surface  of  all  open  seas  (p.  97)  ;  on  the 
currents  as  dependent  on  the  prevailing  winds,  the  unequal 
saltness  of  the  sea,  and  the  configuration  of  the  coasts  (p. 
139) ;  the  directions  of  the  wind  as  resulting  from  differ- 
ences of  temperature,  &c.  Excellent  likewise  are  the  con- 
siderations on  the  general  equinoctial  current,  from  east  to 
west,  as  the  cause  of  the  gulf-stream  which  begins  at  Cape 
St.  Augustine  and  breaks  forth  between  Cuba  and  Florida 
(p.  140).  The  directions  of  the  current  along  the  Western 
African  coast,  between  Cape  Verd  and  the  island  of  Fer- 
nando Po  in  the  gulf  of  Guinea,  are  most  accurately  de-  I 


scribed.  Varenius  considers  sporadic  islets  to  be  "  the  ele- 
vated ocean-bed  ;"— "  magna  spiritum  inclusorum  vi,  sicut 
aliquando  montes  e  terra  protrusos  esse  quidam  scribunt" 
(p.  215).  The  edition  of  1681,  by  Newton  (auctior  et  emen- 
dattor),  unfortunately  has  no  additions  by  this  great  man. 
There  is  no  mention  of  the  spheroidal  flattened  figure  of  the 
earth,  although  Richer's  pendulum  experiments  were  pub 
lished  nine  years  before  the  Cambridge  edition,  but  New 
ton's  "  Principia  mathematica  philosophise  naturalis"  was 
only  communicated  in  manuscript  to  the  Royal  Society  in 
1686.  There  is  much  uncertainty  about  the  native  country 
of  Varenius.  According  to  Jocher,  he  was  bom  in  Eng- 
land ;  according  to  the  **  Biographie  Universelle"  (torn, 
ilvii.  p.  495),  in  Amsterdam  :  but  the  dedication  of  the 
Universal  Geography  to  the  burgomasters  of  this  city  show? 
that  both  assertions  are  equally  false.  Varenius  expressly 
says  that  he  had  fled  to  Amsterdam,  *'  his  native  town  hav- 
ing been  burnt  to  ashes  and  completely  destroyed  in  the 
long  war."  These  words  appear  to  refer  to  Northern  Ger- 
many, and  the  ravages  of  the  30  Years'  War.  Varenius 
likewise  remarks,  in  the  dedication  of  his  "  Descriptio  Reg- 
ni  Japonicae"  (Amst.  1649)  to  the  Hamburg  Senate,  that  he 
had  made  his  first  studies  at  the  Hamburg  Gymnasium.  It 
is  probably  incontrovertible  that  this  acute  geographer  was 
a  German,  and,  moreover,  of  Liineburg.  (Witten's  M6m. 
Theol.  1685,  p.  2142 ;  Zedler's  Universal  Lexicon,  1745, 
part  xlvi.  p.  187.) 

8  (20.)— Charles  Ritter's  Geography  in  relation  to  Nature 
and  the  History  of  Man,  or  general  comparative  geography. 

9  (20.) — Koff/iOf,  in  its  original  and  proper  meaning,  sig- 
nified ornament  (for  men,  women,  and  horses) ;  figuratively, 
order,  tvralia,  and  ornament  of  speech.   The  ancients  unan- 
imously assure  us  that  Pythagoras  was  the  first  to  employ 
this  word  in  the  sense  of  order  of  the  world,  or  world  itself. 
Not  having  written  himself,  the  earliest  proofs  are  in  the 
fragments  of  Philolaus  (Stob.  Eclog.  pp.  360,  460  ;  Heeren's 
Philolaos,  by  Boeckh,  pp.  62,  90).     We  do  not  cite  Timaeus 
of  Locrus,  his  authenticity  being  doubtful.     Plutarch  (de 
plac.  phil.  ii.  1)  decidedly  says  that  Pythagoras  was  the 
first  to  call  the  whole  universe  Cosmos,  by  reason  of  the  or- 
der observed  therein  :   (likewise  Galen,  hist.  phil.  p.  429). 
In  its  new  meaning,  the  word  passed  from  the  philosophical 
school  to  the  poets  of  nature  and  the  prosaists.     Plato  con- 
tinues to  call  the  celestial  bodies  Uranos  ;  but  he  still  styles 
the  order  of  the  world  Cosmos :  and,  in  the  Timsus  (p.  30, 
B.),  the  universe  is  called  a  soul-endowed  animal  (Koaftos 
X^dovliirpvxov).    Compare,  on  the  immaterial  world-arran- 
ging spirit,  Anaxagoras  Claz.  (ed.  Shaubach,  p.  Ill)  and 
Plutarch  (op,  cit.  ii.  3).     With  Aristotle  (de  Caelo,  i.  91), 
Cosmos  is,  "  World  and  its  Arrangement ;"  is  is  also  con- 
sidered as  specially  divisible  into  the  sublunary  world,  and 
the  higher  above  the  moon  (Meteor,  i.  ii.  1,  and  i.  iii.  13, 
pp.  339,  a,  and  340,  b,  Bekk.).    The  definition  of  Cosmos, 
cited  by  me  in  the  text,  is  from  the  "  Pseudo- Aristoteles  de 
Mundo/'  (cap.  ii.  p.  391),  namely:  Koayni  ian  avarrina  i\ 
ov^avou  Kal  y^j  icat  twv  iv  rovroii  irepiej(pixivu)v  (fujaeuv. 
Atyerat  Si  Kal  iTipois  Koapoi  rf  rtjv  S\u)v  rd|tf  re  Kal  610x60- 
fiTjaii,  h-rrd  Occjv  re  Kat  6ta  Otuv  (f>v^aTTOn(vr].   Most  passages 
of  the  Greek  writers,  on  Cosmos  are  collected — 1.  In  Rich- 
ard Bentley's  polemical  pamphlet  against  Charles  Boyle 
(Opuscula  philologica,  1781,  pp.  347,  445  ;  Dissertation  upon 
the  Epistles  of  Phalaris,  1817,  p.  254)  on  the  historical  ex- 
istence of  Zaleucus,  the  Locrian  legislator :  2.  In  Noeke's 
excellent  Sched.  crit.  1812,  pp.  9—15  :   and  3.  In  Theop. 
Schmidt  ad  Cleom.  cycl.  theor.  met.  I.  i.  pp.  ix.  1,  99.  The 
closer  meaning  of  Cosmos  was  likewise  used  in  the  plural 
(Plut.  i.  5),  as,  either  every  star  (celestial  body)  was  so 
called  (Stob.  i.  p.  514 ;  Plut.  ii.  31),  or  many  singular  sys- 
tenas  (world-islands)  were  assumed  in  infinite  space,  each 
having  a  sun  and  moon  (Anaxag.  Claz.  fragm.  pp.  89,  93, 
120  ;  Brandis's  History  of  Grxco- Roman  Philosophy,  voL  i. 
p.  252).     As  each  group  became  a  Cosmos,  the  universe  rd 
irdv  receives  a  higher  signification  distinct  from   Cosmos 
(Plut.  ii.  1).     The  last  word  is  used  for  the  Earth  only  a 
long  time  after  the  Ptolemaic  age.     Bockh  has  communica- 
ted inscriptions  in  praise  of  Trajan  and  Hadrian  (Corp. 
Insc.  GraEC.  torn.  i.  No*-  334,  1306),  wherein  icoff/to;  is  used 
for  oiKOVfiivr],  just  as  we  often  understand  by  world  only 
the  earth.     The  above-mentioned  strange  threefold  divisioa 
of  space  into  Olympus,  Cosmos,  and  Uranos,   (Stob.  i.  p. 
488;  Philolaos,  pp.  94—102)  refers  to  the  different  regions 
which  surround  the  hearth  of  the  universe,  the  Pythagorean 


26 


NOTES  TO  PRECEDING  SECTION. 


'EffTio  ToS  -navrdi.  The  inner  region,  between  the  earth 
and  moon,  the  realm  of  the  variable,  is  termed  Uranos  in 
the  Fragment.  The  middle  portion,  that  of  the  unchange- 
able orderly  circulating  planets,  is  exclusively  termed  Cos- 
mos, after  a  very  partial  view.  The  exterior  region,  a  fiery 
one,  is  the  Olympus.  "  If,"  says  that  profound  diver  into 
the  affinities  of  language,  Bopp — "  if  we  derive  Kdafios  from 
the  Sanscrit  root  s^ud',  purificari,  as  Pott  has  done  (Etymol. 
Researches,  part  i.  pp.  39,  252),  we  must  regard,  in  respect 
to  the  sounds — 1.  that  the  Greek  k  (in  Koa/Jios)  has  proceed- 
ed from  the  palatal  5,  (expressed  by  Bopp  with  an  s'  and* 
Pott  with  a  (;,)  like  icKa,  decern,  Gothic  taihun,  from  the 
ladian  das'an  ;  2.  that  the  Indian  d' regularly  corresponds 
(Compar.  Gramm.  0  99)  to  the  Greek  d,  whence  we  clearly 
ascertain  the  relation  oi  KoayiOi  (for  KoOfios)  to  the  Sanscrit 
root  s'wd',  whence  Kadapos-  Another  Indian  word  for  World 
is  g'agat  (pronounce  dschagat),  properly  meaning  the  going, 
as  a  participle  from  g'a-gdmi,  I  go  (from  the  root  gd)."  In 
the  inner  circle  of  Hellenic  etymology,  Kdafioi  is  (according 
to  Etym.  M.  p.  532,  12)  nearest  connected  with  Aca^u),  or 
rather  Kaivvixai,  whence  KEKaojiiyos  or  KSKuS^ieyoS'  Here- 
with Welcker  (eine  Cretische  Col.  in  Theben,  p.  23)  con- 
nects the  name  KaS/xos,  as  in  Hesychius  kuSixos  denotes  a 
Cretan  suit  of  armour.  When  the  Romans  introduced  the 
philosophical  technical  language  of  Greece,  they  similarly 
*-nlployed  the  word  mundus,  originally-used  like  Koaixos  for 
female  ornament,  to  express  the  world  or  universe.  En- 
nius  appears  to  have  been  the  first  to  venture  on  this  inno- 
iration :  he  says,  in  a  fragment  preserved  to  us  by  Macro- 


bius  (Sat.  vi.  2),  in  his  strife  with  Virgil,  "mundus  cteli 
vastus  constitit  silentio  ;"  like  Cicero,  "  quem  nos  luceutem 
mundum  vocamus"  (Timaeus  s.  de  univ.  cap.  10).  The 
Sanscrit  root  mond,  whence  Pott  (Etym.  Res.  part  i.  p.  240)  i 
deduces  the  word  mundus,  unites  both  meanings  of  shining 
and  adorning.  Loka  signifies  world  and  men  in  Sanscrit, 
like  the  French  monde,  and,  according  to  Bopp,  is  derived 
from  I6k,  to  see  and  illuminate :  similarly  the  Slavonian 
sivjet  (Grimm's  German  Gramm.  vol.  iii.  p.  394)  is  light  and 
world.  This  word  Welt,  which  the  Germans  now  use,  old 
High  German  wSralt,  old  Saxon  worold,  Anglo-Saxon  vSruld, 
originally  denotes,  according  to  Jacob  Grimm,  only  "  the 
idea  of  time,  sceculum  (age  of  man),  not  the  spacial  mundus." 
Amongst  the  Tuscans,  the  open  mundus  meant  an  inverted 
dome,  which  turned  its  cupola  towards  the  world  below, 
and  imitated  the  heavenly  vault. — (Otf.  Miiller's  Etruscans, 
part  ii.  pp.  96,  98,  143.)  In  its  narrower  telluric  significa- 
tion, the  world  appears  in  the  Gothic  language  as  the  sea- 
{marei,  meri)  surrounded  horizon,  as  merigard,  a  sea-gar 
den. 

10  (20.) — Vide  about  Ennius,  Leopold  Krahner's  acute 
researches  in  his  "  Grundlinien  zur  Geschichte  desVerfalls 
der  Romischen  Staats-Religion,"  1837,  pp.  41—45.  Proba- 
bly Ennius  did  not  draw  from  the  Epicharmic  pieces,  but 
from  poems  which  went  by  the  name  of  Epicharmus,  and 
were  written  according  to  his  system. 

n  (p.  21.)— Gellius,  Noct.  Att,  v.  18. 

12  (p.  23.)— Schelling's  Bruno  on  the  Divine  and  Natural 
Principle  of  Things,  p.  181. 


PICTURE  OF  NATURE. 

GENERAL  SURVEY  OP  NATURAL  PHENOMENA, 


When  the  human  mind  essays  to  dominate 
matter — in  other  words,  to  comprehend  the 
world  of  physical  phenomena — when  we  strive, 
in  thoughtful  contemplation  of  existing  things, 
to  penetrate  the  life  of  Nature  in  its  ample  ful- 
ness, and  to  unveil  the  empire  of  her  various 
forces,  we  feel  ourselves  raised  to  an  eminence, 
whence,  in  the  wide-spread  horizon  around,  in- 
dividualities present  themselves  gathered  into 
groups,  and  surrounded  with  a  kind  of  vaporous 
haze.  This  figurative  language  is  used  to  give 
some  idea  of  the  point  of  view  from  which  we 
shall  here  attempt  to  survey  the  universe,  and 
to  present  it  for  contemplation  in  both  of  its 
spheres — the  celestial  and  the  terrestrial.  The 
boldness  of  such  an  attempt  I  do  not  conceal 
from  myself  Of  all  the  kinds  of  representa- 
tion to  which  these  pages  are  dedicated,  that 
of  the  General  Picture  of  Nature  is  by  far  the 
most  difficult.  Here  we  do  not  condescend 
upon  the  minutiae  of  individual  forms  ;  we  only 
pause  upon  the  grander  masses,  whether  in  the 
world  of  fact  or  of  idea.  By  separation  and 
subdivision  of  phenomena,  by  a  kind  of  forebo- 
ding penetration  of  the  play  of  obscure  forces, 
by  liveliness  of  representation,  in  which  the 
impression  made  on  the  senses  is  reflected  true 
to  nature,  may  we  hope  to  grasp  and  to  describe 
the  Infinite  All  (rd  nuv),  in  a  way  that  shall  be- 
come the  grand  word  Cosmos,  in  its  sense  of 
Universe,  Order  of  Creation,  Beauty  of  Ar- 
rangement. May  the  infinite  diversity  of  ele- 
ments that  crowd  into  a  picture  of  Nature  so 
vast,  not  disturb  the  harmonious  impression  of 
repose  and  unity,  which  it  is  the  last  purpose 
of  every  literary  and  artistical  composition  to 
convey ! 

We  begin  with  the  depths  of  space,  and  the 
region  of  the  farthest  nebulae;   we  descend, 
step  by  step,  through  the  stratum  of  stars  to 
which  our  solar  system  belongs,  and  at  length 
set  foot  on  the  air-  and  sea-surrounded  sphe- 
roid we  inhabit,  discussing  its  form,  its  tem- 
perature, and  its  magnetical  tension,  till  we 
reach  the  life,  that,  under  the  stimulus  of  light, 
is  evolved  upon  its  surface.     A  picture  of  the 
universe,  therefore,  worked  with  a  few  grand  j 
touches,  comprehends  the  immeasurable  depths  ^ 
of  space,  as  well  as  the  microscopic  organisms  ^ 
of  the  vegetable  and  animal  kingdom  that  live  ' 
in  our  stagnant  waters,  and  cling  to  the  weath- 
erworn faces  of  our  rocks.     All  that  the  most 
careful  study  of  nature,  in  its  present  direction,  | 
up  to  the  passing  hour,  has  discovered,  consti- 
tutes the  material  in  harmony  with  which  the 
canvass  is  to  be  filled  ;  it  includes  within  itself 
the  evidence  of  its  truth  and  endurance.     A  de- 
scriptive natural  picture,  however,  such  as  we 
would  indicate  it  in  these  prolegomena,  must  i 
not  present  all  the  individual,  all  the  single  ;  it 
needs  not,  to  be  complete,  an  enumeration  of 
all  the  forms  of  life,  of  every  natural  thing  and 


natural  process.  Striving  against  the  tenden- 
cy to  endless  subdivision  of  the  Known  and 
the  Collected,  the  thinker  who  orders  and  ar- 
ranges must  rather  seek  to  escape  the  danger 
of  empirical  overabundance.  A  considerable 
mass  of  the  qualitative  forces  of  matter,  or,  to 
speak  in  the  language  of  the  philosophers  of 
nature,  of  its  qualitative  manifestations  offeree, 
is  certainly  still  unknown.  The  discovery  of 
unity  in  totality  must,  therefore,  and  on  this 
account,  remain  imperfect.  Beside  the  joy, 
mixed  as  it  were  with  wo,  which  we  feel  in 
knowledge  possessed,  there  dwells  in  the  eager 
spirit,  unsatisfied  with  the  present,  the  longing 
after  yet  untrodden,  yet  unimagined,  regions 
of  knowledge.  But  such  a  longing  only  knits 
more  firmly  the  bond  which,  in  virtue  of  ancient 
laws,  controlling  the  very  core  of  the  world  of 
thought,  binds  the  Sentient  with  the  Supersen- 
tient ;  it  vivifies  the  commerce  between  that 
"  which  the  mind  receives  from  the  world  with- 
out, and  that  which,  from  its  own  depths,  it 
gives  back." 

If  nature,  therefore,  or  the  conception  form- 
ed of  natural  things  and  natural  phenomena, 
considered  in  its  boundary  and  contents,  be  in- 
finite, so  is  she  also,  with  reference  to  the  in- 
tellectual powers  of  man,  an  incomprehensible, 
and,  in  the  general  causal  co-operation  of  her 
forces,  an  unresolvable  problem.  Such  an  avow- 
al is  proper  where  existence  and  evolution  (Be- 
ing and  to  Be)  are  only  subjected  to  immediate 
scrutiny,  in  circumstances  where  the  empirical 
path,  and  the  strictly  inductive  method,  cannot 
be  quitted  for  a  moment.  But  if  the  ceaseless 
longing  to  comprehend  nature  in  its  totality  re- 
main unsatisfied,  the  history  of  human  progress 
in  contemplating  nature,  which  is  reserved  for 
another  section  of  the  prolegomena,  teaches 
us,  on  the  other  hand,  how,  in  the  course  of 
centuries,  mankind  have  gradually  attained  to 
a  partial  insight  into  the  relative  dependence 
of  phenomena.  It  is  my  duty  to  pass  in  review 
the  contemporaneously  known,  according  to 
the  measure  and  the  boundaries  of  the  present. 
In  all  that  is  mobile,  changeable  in  space,  mean 
numerical  values  are  the  ultimate  object — they 
are  the  expression,  indeed,  of  physical  laws ; 
they  show  us  the  stable  in  the  change  and  in 
the  flight  of  phenomena.  The  progress  of  our 
modern  measuring  and  weighing  physics  is  par- 
ticularly distinguished  by  the  attainment  and 
correction  of  the  mean  values  of  certain  quan- 
tities or  masses  ;  and  here,  as  dwelt  on  by  the 
old  Italic  school,  but  in  a  wider  sense,  we  find 
those  wide-spread,  hieroglyphic  signs,  numbers, 
coming  into  play  as  powers  in  Cosmos. 

The  serious  inquirer  rejoices  in  the  simplici- 
ty of  numerical  relations,  by  which  are  indica- 
ted the  dimensions  of  the  celestial  spaces,  the 
magnitude  of  the  bodies  they  enclose,  and  the 
periodic  perturbations  which  these  suffer ;  the 


28 


PICTURE  OF  NATURE. 


threefold  elements  of  terrestrial  magnetism  ; 
the  mean  pressure  of  the  atmosphere,  and  the 
quantity  of  heat  which  the  sun  dispenses  in  the 
course  of  every  year,  and  in  each  division  of  the 
year,  over  the  several  points  of  the  solid  or 
liquid  surface  of  our  planet.  The  poet  of  na- 
ture is  less  satisfied  with  such  results  ;  the  ap- 
petite for  the  marvellous,  inherent  in  the  many, 
is  less  appealed  to  by  them.  The  poet  com- 
plains that  science  has  made  a  desert  of  na- 
ture ;  the  vulgar  find  many  questions  returned 
to  them  with  doubtful  solutions,  or  declared  un- 
answerable, which  formerly  were  met  without 
misgivings.  In  her  graver  form,  in  her  less 
ample  garments,  she  is  robbed  of  that  seducing 
grace  by  which  the  dogmatic  and  symbolic 
physics  of  former  times  sought  to  deceive  the 
reason,  to  occupy  the  imagination.  Long  be- 
fore the  discovery  of  the  New  World,  it  was 
thought  that  land  could  be  seen  in  the  West 
from  the  Canaries  and  the  Azores.  These 
were  phantasms,  not  produced  by  any  extraor- 
dinary refraction  of  rays  of  light,  but  merely  by 
a  longing  for  the  distant,  for  that  which  lies  be- 
yond the  present.  The  natural  philosophy  of 
the  Greeks,  and  the  physics  of  the  middle  ages, 
and  even  of  much  later  centuries,  presented 
swarms  of  such  fantastic  forms  to  the  imagina- 
tion. The  mental  eye  still  essays  to  pass  the 
horizon  of  limited  knowledge,  even  as  the  ma- 
terial eye  endeavours  to  pierce  the  natural  ho- 
rizon from  an  island  height  or  shore.  Faith  in 
the  unusual  and  wonderful  gives  definite  out- 
lines to  every  product  of  imagination,  and  the 
realm  of  fancy,  a  strange  land  of  cosmological, 
geognostical,  and  magnetic  dreams,  is  inces- 
santly blended  with  the  world  of  reality. 

Nature,  in  the  manifold  significance  of  the 
term,  now  as  implying  entireness  of  that  which 
is,  and  is  becoming ;  now  as  an  inherent  ac- 
tuating force ;  and  again,  as  the  mysterious 
prototype  of  all  phenomena,  reveals  itself  to 
the  simple  sense  and  feeling  of  mankind  as 
something  more  especially  terrestrial,  as  some- 
thing that  is  near  akin  to  them.  We  seem  at 
first  to  recognize  our  proper  home  in  the  liv- 
ing circle  of  organic  formation.  Where  the 
bosom  of  the  earth  is  adorned  with  fruits  and 
flowers,  where  it  supports  and  nourishes  in- 
numerable kinds  of  animals,  there  does  the  im- 
age of  nature  come  up  in  living  tints  before  the 
soul.  We  are  more  immediately  connected 
with  the  earth,  with  the  terrestrial ;  the  cano- 
py of  heaven,  inlaid  with  shining  stars,  the 
boundless  realms  of  space,  belong  to  a  picture, 
the  magnitude  of  whose  elements — ^hosts  of 
suns,  glimmering  nebulous  specks,  infinity  of 
space — arouse  our  wonder  and  amazement,  in- 
deed, but  still  remain  foreign  to  our  mind  and 
feelings,  through  a  sense  of  desolation,  and  a  to- 
tal want  of  immediate  impression  through  the 
presence  of  organic  life.  To  mankind  at  large, 
therefore,  the  heaven  and  the  earth  have  still  re- 
mained distinct,  as  the  above  and  the  below  in 
space,  in  consonance  with  the  earliest  notions 
entertained  on  the  subject.  Were  a  picture  of 
nature  at  large,  then,  solely  intended  to  meet  the 
requirements  of  sense,  it  would  have  to  be  be- 
gun with  a  representation  of  our  proper  home 
for  a  foundation.  It  would  first  portray  the 
earth  in  its  dimensions  and  configuration,  in  its 
increasing  densitv  and  temperature  as  its  cen- 


tre was  approached,  in  its  solid  and  fluid  su- 
perposed strata ;  it  would  exhibit  the  severance 
of  sea  and  land  ;  the  life  which  in  both  is  evolv- 
ed as  cellular  tissue  in  plants  and  animals ; 
and  the  atmospheric  ocean,  with  its  waves 
and  currents,  from  the  bottom  of  which  wood- 
crested  mountain-chains  emerge  like  reefs  and 
shoals.  After  this  exhibition  of  purely  terres- 
trial relations,  the  eye  would  rise  to  the  celes- 
tial spaces  ;  the  earth,  the  well-known  seat  of 
organic  formative  processes,  would  now  be 
contemplated  as  a  planet.  It  would  fall  into 
the  series  of  bodies  which  circulate  around  one 
of  the  innumerable  host  of  self-efFulgent  stars. 
This  sequence  of  ideas  indicates  the  path  pur- 
sued in  the  first  contemplation  of  nature  by 
the  senses  ;  it  still  reminds  us  of  the  "sea-sur- 
rounded disc  of  earth,"  which  supported  heav- 
en :  it  sets  out  from  the  station  of  simple  per- 
ception, from  the  known  and  the  near,  to  the 
unknown  and  the  far  removed.  It  corresponds 
with  the  method  observed  in  our  elementary 
astronomical  works,  which  pass  from  the  ap- 
parent to  the  true  motions  of  the  heavenly 
bodies. 

In  a  work,  however,  which  undertakes  to 
speak  of  the  actually  known,  of  that  which,  in 
the  present  state  of  science,  is  held  for  certain, 
or  which,  in  various  degrees,  is  looked  upon  as 
probable,  but  which  does  not  propose  to  give 
the  details  upon  which  results  are  founded, 
another  course  of  procedure  appears  advisable. 
Here  we  do  not  set  out  from  the  subjective 
point  of  view,  from  that  which  regards  human 
interests.  The  terrestrial  can  only  appear  as 
a  part  in  the  whole,  and  as  subordinate  to  this. 
The  view  taken  of  nature  must  be  general,  it 
must  be  grand  and  free,  not  contracted  by  no- 
tions of  vicinity,  of  affection,  of  relative  use- 
fulness. A  physical  cosmography,  or  true  pic- 
ture of  the  universe,  cannot,  therefore,  com- 
mence with  the  terrestrial ;  it  must  needs  be- 
gin with  the  contents  of  heavenly  space.  But 
as  the  spheres  of  contemplation,  in  reference 
to  space,  contract,  the  amount  of  individual 
details,  the  variety  of  physical  phenomena, 
knowledge  of  the  qualitative  heterogeneous- 
ness  of  matter,  augment.  From  regions  in 
which  we  can  only  distinguish  the  empire  of 
the  universal  laws  of  gravitation,  we  descend 
to  our  planet,  to  the  intricate  play  of  forces 
that  constitute  the  life  of  the  globe.  The  nat- 
ural descriptive  method  now  sketched  out  is 
opposed  to  that  which  establishes  conclusions. 
The  one  enumerates  what  the  other  demon- 
strates. 

Man  assumes  the  external  world  into  his  in- 
terior by  means  of  certain  organs.  The  phe- 
nomena of  light  make  us  aware  of  the  exist- 
ence of  matter  in  the  farthest  depths  of  heav- 
en. The  eye  is  the  organ  by  which  the  uni- 
verse is  perceived,  and  the  discovery  of  tele- 
scopic vision  some  century  and  a  half  ago  has 
conferred  a  power  upon  later  generations  whose 
limits  have  not  yet  been  reached.  The  first 
and  most  general  consideration,  in  Cosmos  is 
that  of  the  contents  of  space,  the  contempla- 
tion of  division  in  matter,  of  Creation,  as  we 
are  accustomed  to  designate  all  that  is  or  is 
about  to  be.  We  perceive  matter  here  aggre- 
gated into  revolving  and  circulating  masses  of 
most  dissimilar  density  and  magnitude  ;  there 


GENETIC  EVOLUTION— NEBULA. 


99 


diffused  in  the  shape  of  self-luminous  clouds  or 
vapours.  If  we  first  turn  our  attention  to 
these  NEBULA  (world-mists,  separating  into 
determinate  forms),  we  discover  that  they  are 
in  course  of  suffering  change  in  their  state  of 
aggregation.  They  present  themselves  to  our 
eyes  apparently  of  small  dimensions,  as  round- 
ed or  elliptical  discs,  single  or  in  pairs,  occa- 
sionally connected  by  a  luminous  streak  ;  of 
larger  size  they  are  variously  shaped— elonga- 
ted or  shooting  out  into  several  branches ;  or 
they  look  fan-shaped  ;  or  they  form  sharply  de- 
fined rings  with  dark  included  centres.  These 
nebulae  are  believed  to  be  in  process  of  various 
and  progressive  changes,  according  as  the  star- 
dust  or  vapour  composing  them  is  becoming 
condensed,  in  harmony  with  the  laws  of  at- 
traction, around  one  or  several  nuclei.  The 
number  of  these  unresolvable  nebulae — nebulae 
in  which  the  most  powerful  telescope  does  not 
enable  us  to  distinguish  a  single  star — that 
have  been  reckoned,  and  their  position  in  space 
determined,  now  amounts  to  about  one  thou- 
sand five  hundred. 

The  genetic  evolution,  the  ceaseless,  pro- 
gressive formation  that  appears  to  be  going  on 
in  these  portions  of  infinite  space,  has  led  re- 
flective minds  to  the  analogy  of  organic  phe- 
nomena. As  in  our  woods  we  observe  the 
same  kind  of  tree  in  every  stage  of  growth  at 
the  same  time,  and  from  this  view,  this  co-ex- 
istence, derive  the  impression  of  progressive 
vital  development ;  so  do  we,  in  the  mighty 
garden  of  the  universe,  recognise  different  sta- 
ges in  the  progressive  formation  of  stars.  The 
process  of  condensation,  indeed,  which  Anax- 
imenes  and  the  Ionic  school  once  taught,  seems 
here  to  proceed,  as  it  were,  under  our  eyes. 
This  object  of  inquiry  and  conjecture  is  pecu- 
liarly attractive  to  the  imagination.  That 
which,  in  the  circles  of  life,  and  in  all  the  in- 
ternal impulsive  forces  of  the  universe,  fetters 
us  so  unspeakably,  is  less  the  recognition  of 
Being,  than  of  what  is  About  to  be ;  even 
though  the  latter  be  nothing  more  than  a  new 
condition  of  matter  already  extant ;  for  of 
proper  creation  as  an  efficient  act,  of  a  proto- 
genesis  of  matter,  of  entity  succeeding  nonen- 
tity, we  have  neither  conception  nor  expe- 
rience. 

It  is  not  merely  by  a  comparison  of  the  various 
moments  of  development  which  are  exhibited 
by  nebulae,  in  greater  or  less  degrees  of  con- 
densation of  their  interiors,  that  astronomers 
have  inferred  changes  in  their  structure.  We 
have  now  a  series  of  observations  made  imme- 
diately upon  particular  nebulae,  on  the  one  in 
Andromeda,  on  that  which  occurs  in  the  ship 
Argo,  and  also  in  the  flocky  portion  of  that 
which  presents  itself  in  Orion,  which  led  to  the 
belief  that  actual  changes  in  their  form  have 
been  observed.  Inequality  of  power  of  light  in 
the  instruments  employed,  however,  different 
states  of  our  atmosphere,  and  other  optical 
conditions,  it  must  be  admitted,  render  a  por- 
tion of  these  results  questionable  as  true  his- 
torical data. 

The  peculiar  multiform  nebulae,  the  several 
parts  of  which  have  different  degrees  of  bright- 
ness, and  which,  with  a  diminution  of  their 
areas,  will  perhaps  become  concentrated  into 
stars,  and  those  nebulae  that  have  been  entitled 


planetary,  the  round  or  somewhat  oviform 
discs  of  which  shine  in  every  part  with  a  mild 
and  equable  light,  are  not  to  be  confounded 
with  nebulous  stars.  Here  there  is  no  appear- 
ance of  a  star  projected  accidentally,  as  it 
might  seem,  upon  a  remote  nebulous  ground  ; 
no,  the  vaporiform  matter,  the  light-cloud, 
forms  a  single  mass  with  the  star  which  it  sur- 
rounds. From  the  frequently  very  considera- 
ble magnitude  of  their  apparent  diameters,  and 
the  distances  whence  they  glimmer,  both  plan- 
etary nebulae  and  nebulous  stars  must  possess 
enormous  dimensions.  New  and  acute  con- 
siderations(')  on  the  very  different  influence  of 
distance  upon  the  intensity  of  the  light  of  a 
disc  of  measurable  diameter,  or  of  a  single 
self-luminous  point,  make  it  not  improbable  that 
planetary  nebulae  are  extremely  remote  nebu- 
lous stars,  in  which  the  distinction  between  the 
central  star  and  its  hazy  envelope  has  disap- 
peared even  to  our  telescopic  vision. 

The  brilliant  zones  of  the  southern  celestial 
hemisphere,  between  the  parallels  of  50°  and 
80°,  are  particularly  rich  in  nebulous  stars,  and 
concentrated  but  unresolvable  nebulae.  The 
Magellanic  clouds  which  circulate  round  the 
starless,  desolate  south  pole  (especially  the 
larger  of  the  two),  appear,  according  to  the  la- 
test observations('),  "  as  a  wonderftil  mixture 
of  groups  of  stars,  of  globular  clusters  of  nebu- 
lous stars  of  different  magnitudes,  and  of  un- 
resolvable nebulae,  which,  producing  a  general 
brightness  of  the  field  of  vision,  form  a  kind  of 
back-ground  to  the  picture."  The  aspect  of 
these  clouds,  of  the  light-streaming  ship  Argo, 
of  the  milky  way  between  the  Scorpion,  the 
Centaur,  and  the  Cross — the  whole  of  the 
charming  landscape  presented  by  the  southern 
heavens,  has  left  an  indelible  impression  upon 
my  mind.  The  zodiacal  light,  which  rises  like 
a  pyramid  from  the  sun,  and  in  its  gentle  ra- 
diance proves  another  of  the  eternal  ornaments 
of  the  tropical  night,  is  either  an  immense  neb- 
ulous ring  rotating  betwixt  the  earth  and  Mars, 
or  (but  this  is  less  probable)  it  is  the  outermost 
stratum  of  the  sun's  atmosphere  itself  Be- 
sides these  luminous  clouds  and  nebulae  of  de- 
terminate form,  accurate  and  still  coinciding 
observations  seem  to  proclaim  the  existence 
and  general  diffusion  of  an  infinitely  rare,  and 
apparently  not  self-luminous  matter,  which, 
OFFERING  RESISTANCE,  rcvcals  Itsclf  by  lesscu- 
ing  the  eccentricity,"  and  shortening  the  period 
of  revolution  of  Encke's,  and  perhaps  also  of 
Biela's  comet.  This  impeding  aethereal  and 
cosmic  matter  may  be  conceived  as  in  motion, 
despite  its  original  tenuity  as  gravitating,  as 
condensed  in  the  vicinity  of  the  great  body  of 
the  sun,  and  even  as  increased  in  the  course 
of  myriads  of  years,  by  vapours  thrown  off 
from  the  tails  of  comets. 

If  we  now  pass  on  from  the  nebulous  matter 
of  the  infinities  of  heavenly  space  (ovpavov  x^p^ 
To^'),  here  scattered  without  form  or  boundary, 
a  cosmic  world-ether,  there  condensed  into  neb- 
ulous specks,  to  the  .conglobated  solid  portions 
of  the  universe,  we  approach  a  class  of  phenom- 
ena which  are  exclusively  designated  by  the  title 
of  stars,  or  fixed  stars.  And  here,  too,  the  de- 
gree of  solidity  or  density  of  the  conglobated 
matter  is  different.  Our  own  solar  system  pre- 
sents us  with  every  grade  of  mean  density ;.  in 


30 


PICTURE  OF  NATURE. 


other  terms,  of  difference  betwixt  the  relations 
of  volume  and  mass.  When  we  compare  the 
planets  from  Mercury  to  Mars  with  the  Sun 
and  with  Jupiter,  and  Mars  and  Jupiter,  again, 
with  Saturn,  we  proceed  in  a  descending  scale 
of  density  ;  selecting  familiar  objects  as  stand- 
ards of  comparison,  from  matter  of  the  density 
of  antimony,  to  matter  of  the  density  of  honey, 
of  water,  and  of  pine  timber.  In  Comets, 
which,  numerically  speaking,  constitute  the 
largest  portion  of  the  individualized  physical 
forms  of  our  solar  system,  the  most  concen- 
trated part,  which  we  call  nucleus  or  head, 
still  allows  the  light  of  the  stars  to  pass  through 
it  unrefracted.  The  mass  of  comets,  perhaps, 
never  exceeds  the  five-thousandth  part  of  the 
mass  of  the  earth  :  so  variously  do  the  forma- 
tive processes  meet  us  in  original  and  perhaps 
progressive  conglobations  of  matter.  Setting 
out  from  what  is  most  general,  it  was  especial- 
ly necessary  to  indicate  this  diversity,  not  as  a 
thing  possible,  but  as  a  reality — as  a  datum  in 
universal  space. 

What  Wright,  Kant,  and  Lambert  have  de- 
duced from  the  conclusions  of  pure  reason,  in 
♦regard  to  the  construction  of  the  universe,  to 
the  distribution  of  matter  in  space,  has  been 
established  by  Sir  William  Herschel  upon  the 
securer  basis  of  observation  and  measurement. 
This  great,  inspired,  and  yet  cautious  observer, 
first  cast  the  plumb-hne  into  the  depths  of 
heaven,  to  determine  the  boundaries  and  the 
form  of  the  separate  cluster  of  stars  which  we 
inhabit ;  and  he  was  the  first  who  ventured  to 
offer  an  explanation  of  the  relations  in  point 
of  position  and  distance,  of  remote  nebulous 
specks  to  our  own  astral  system.  William 
Herschel,  as  the  elegant  inscription  on  his 
monument,  at  Upton,  says  so  happily,  "broke 
through  the  barriers  of  the  heavens  {ccdorum 
perrupit  daustra).^^  Like  Columbus,  he  forced 
his  way  into  an  unknown  ocean,  and  caught  a 
glimpse  of  coasts  and  groups  of  islands  whose 
true  position  it  is  reserved  for  future  centuries 
to  determine. 

Considerations  on  the  varying  intensity  of 
the  light  of  the  stars,  and  on  their  relative  num- 
bers— in  other  words,  their  numerical  abun- 
dance or  rarity  in  equal  fields  of  the  telescope 
— have  led  to  inferences  concerning  the  une- 
qual distances  and  distribution  in  space  of  the 
strata  which  they  compose.  Such  inferences, 
considered  as  leading  to  cfrcumscription  of  the 
several  portions  of  the  universe,  do  not,  how- 
ever, admit  of  the  same  degree  of  mathemati- 
cal certainty  as  is  attained  in  all  that  concerns 
our  own  solar  system,  the  revolutions  of  double 
stars,  with  unequal  velocities,  around  a  com- 
mon centre  of  gravity,  and  the  apparent  or  ac- 
tual motions  of  the  stars  in  general.  W^e  are 
almost  disposed  to  compare  the  chapter  in  our 
physical  cosmography  which  discusses  the  neb- 
ulous specks  of  heaven,  with  the  mythological 
portion  of  general  history.  They  both  begin 
alike — the  one  in  the  twilight  of  remote  anti- 
quity, the  other  in  the  depths  of  illimitable 
space ;  and  where  reality  threatens  to  disap- 
pear, fancy  is  doubly  excited  to  draw  from  her 
own  abundance,  and  to  give  form  and  endurance 
to  the  Indefinite  and  the  Changeable. 

If  we  compare  the  universe  with  one  of  the 
isle-studded  oceans  of  our  planet,  we  think 


that  we  can  perceive  matter  distributed  group, 
wise :  now,  collected  into  unresolvable  nebu- 
lous specks  of  various  age ;  now  condensed 
around  one,  or  several,  nuclei,  and  again  round- 
ed into  clusters  of  stars,  or  isolated  sporades. 
The  cluster  of  stars,  the  islet  in  the  infinity  of 
space,  to  which  we  belong,  forms  a  lenticular, 
compressed,  and  everywhere  distinct  or  separ- 
ate layer,  the  longer  axis  of  which  has  been 
estimated  at  from  seven  to  eight  hundred,  and 
the  shorter  axis  at  some  one  hundred  and  fifty, 
distances  of  Sirius.  Presuming  that  the  paral- 
lax of  Sirius  is  not  greater  than  that  of  the 
bright  star  in  the  Centaur,  which  has  been  ac- 
curately ascertained  (viz.  0"  9128),  light  would 
pass  through  one  distance  of  Sirius  from  the 
Earth  in  three  years,  whilst,  from  Bessel's  ad- 
mirable earlier  paper(*)  on  the  parallax  (0"-3483) 
of  the  remarkable  star  in  Cygnus  (the  61st),  the 
very  distinct  proper  motion  of  which  must  ad- 
mit of  a  very  close  approximation,  it  follows, 
that  the  light  of  this  star  only  reaches  us  after 
travelling  through  space  for  some  nine  years 
and  a  quarter.  Our  stratum  of  stars,  a  disc 
of  relatively  moderate  thickness,  is  divided, 
through  one-third  of  its  extent,  into  two  arms ; 
and  it  is  thought  that  we  are  placed  somewhat 
near  to  this  division — nearer  to  Sirius  than  to 
the  constellation  of  the  Eagle,  almost  in  the 
middle  of  the  material  extension  of  the  layer, 
in  the  line  of  its  thickness,  or  lesser  axis. 

This  position  of  our  solar  system,  and  the 
formation  of  the  whole  lens,  are  deduced  by 
means  of  a  process  of  what  has  been  aptly  des- 
ignated gauging  the  heavens ;  i.  e.  reckoning 
the  number  of  stars  included  in  the  same  field 
of  the  telescope  turned  on  every  side  around. 
The  increasing,  or  decreasing,  number  of  stars 
measure  the  depth  or  thickness  of  the  layer  in 
different  directions.  Precisely  as  the  point  at 
which  the  plummet  strikes  the  bottom  deter- 
mines the  length  of  the  line  that  it  is  cast  from 
the  hand,  do  these  soundings  of  the  heavens 
give  the  lengths  of  the  visual  ray,  when  the  bot- 
tom of  the  starry  depths,  or  rather,  and  more 
correctly,  as  there  is  neither  above  nor  below 
here,  when  the  limits  of  starry  space  are  at- 
tained. In  the  direction  of  the  longer  axis,  and 
where  the  greatest  numbers  of  stars  lie  one 
behind  another,  the  eye  perceives  the  farthest 
off  thickly  crowded  together,  connected,  as  it 
seems,  by  a  milky  glimmer  (light-mist),  and  pro- 
jected, in  perspective,  upon  the  visible  vault 
of  heaven  in  the  form  of  a  belt  or  girdle.  This 
narrow  belt  of  beautiful,  but  unequal  radiance, 
for  its  continuity  is  broken  by  less  luminous 
spaces,  divides  into  two  branches,  and,  save 
where  it  is  interrupted  for  a  few  degrees,  forms 
a  great  circle  upon  the  hollow  sphere  of  the 
heavens.  This  is  in  consequence  of  the  po- 
sition of  our  system,  near  the  middle  of  the 
great  astral  group  to  which  it  belongs,  and  al- 
most in  the  plane  of  the  milky  way  itself. 
Were  our  planetary  system  placed  far  without 
the  cluster,  the  milky  way  would  present  itself 
to  the  assisted  eye  as  a  complete  ring,  and.  at 
a  still  greater  distance,  as  a  resolvable  disc- 
shaped nebula. 

Amongst  the  many  self-luminous  bodies,  er- 
roneously designated  fixed  stars,  for  they  are 
all  in  motion,  which  constitute  our  island  in  the 
universe,  our  sun  is  the  only  one  which  we 


THE  PLANETS. 


31 


know,  through  actual  observation,  as  a  central 
body  in  reference  to  the  conglobated  masses 
of  matter,  in  the  shape  of  planets,  comets,  and 
aerolitic  asteroids,  which  revolve  around,  and 
immediately  depend  upon  him.  Among  the 
multiple  or  double  stars  or  suns,  in  so  far  as 
their  nature  has  yet  been  studied,  there  does 
"  not  appear  to  reign  the  same  planetary  depend- 
ence, in  respect  of  relative  motion  and  illumi- 
nation, which  characterizes  our  solar  system. 
Two  or  more  self-luminous  stars,  whose  plan- 
ets and  moons — if  any  such  exist — escape  our 
present  telescopic  powers  of  vision,  revolve 
unquestionably  around  a  common  centre  of 
gravity ;  but  this  centre  falls  in  a  space  that 
perchance  is  filled  with  unaggregated  matter 
(world-mist),  whilst  with  our  sun  it  is  always 
situated  in  the  inner  confines  of  a  visible  cen- 
tral body.  When  we  consider  our  sun  and 
earth,  or  our  earth  and  moon,  as  double  stars, 
and  our  whole  planetary  system  as  a  multiple 
group  of  stars,  the  analogy  with  the  proper 
multiple  or  double  fixed  stars,  which  such  a 
designation  presents  to  the  mind,  extends  no 
farther  than  to  motions  connected  with  sys- 
tems of  attraction  of  different  orders,  quite  in- 
dependently of  light  evolving  processes,  and 
kinds  of  illumination. 

In  this  generalization  of  cosmic  views,  which 
befits  the  sketch  of  a  Picture  of  Nature  or  the 
Universe,  the  solar  system  to  which  our  earth 
belongs  may  be  considered  in  a  two-fold  rela- 
tionship :  immediately,  to  the  several  classes 
of  individualized  conglomerate  matter — to  the 
magnitude,  the  fashion,  the  density,  and  the  dis- 
tance of  the  bodies  of  the  system ;  and,  next,  in 
its  relations  to  other  parts  of  our  astral  system, 
to  the  sun's  change  of  place  within  the  same. 

The  solar  system,  in  other  words,  the  very 
variously  fashioned  matter  which  circulates 
about  the  sun,  consists,  according  to  our  pres- 
ent knowledge,  of  eleven  principal  planets,  of 
eighteen  moons  or  satellites,  and  of  myriads 
of  comets,  three  of  which,  called  planetary 
comets,  never  quit  the  limited  spheres  of  the 
proper  planets.  We  may  further,  with  no 
slight  show  of  propriety,  reckon  as  falling  with- 
al in  the  empire  of  our  sun,  as  included  within  the 
sphere  of  his  central  force — 1st,  a  ring  of  va- 
porous matter,  revolving,  in  all  probability,  be- 
twixt the  orbits  of  Venus  and  Mars,  certainly 
extending  beyond  the  orbit  of  the  earth('),  which 
is  visible  to  us  in  a  pyramidal  form,  and  is 
known  under  the  name  of  the  zodiacal  light ; 
2d,  a  host  of  very  small  asteroids,  whose  or- 
bits either  intersect  the  orbit  of  the  earth,  or 
approach  it  very  nearly,  and  give  occasion  to 
the  phenomena  of  aerolites  and  falling  stars. 
When  we  direct  our  attention  to  the  complexi- 
ty of  formations  which  circulate  about  the  sun 
in  orbits  more  or  less  excentric,  unless,  with 
the  immortal  author  of  the  "  Mechanique  Ce- 
leste," we  regard  the  greater  number  of  com- 
ets as  nebulous  stars  which  sweep  from  one 
central  system  to  another(®),  we  must  confess, 
that  the  planetary  system,  strictly  so  called — 
the  group  of  bodies  which  revolve,  with  their 
attendant  satellites,  in  but  slightly  excentric 
orbits  round  the  sun — constitutes  but  a  small 
portion  of  the  entire  system,  when  the  number, 
not  the  mass,  of  the  individuals  is  made  the 
basis  of  consideration. 


The  telescopic  planets,  Vesta,  Juno,  Ceres, 
and  Pallas,  with  their  mutually  intersecting, 
much  inclined,  and  more  excentric  orbits,  have 
been  viewed  as  constituting  a  kind  of  zone  of 
separation  between  two  divisions  of  our  plan- 
etary system,  and  as  forming  in  themselves  a 
middle  group.  According  to  this  view,  the  in- 
ner planetary  group,  comprising  Mercury,  Ve- 
nus, the  Earth,  and  Mars,  presents  several  re- 
markable points  of  contrast  with  the  outer 
group,  consisting  of  Jupiter,  Saturn,  and  Ura- 
nus(^).  The  inner  planets,  nearer  to  the  sun, 
are  of  moderate  dimensions,  of  greater  density, 
turn  more  slowly  upon  their  axes,  and  very 
nearly  in  the  same  period  of  time  (twenty-four 
hours),  are  flattened  towards  their  poles  in  a 
less  degree,  and,  with  one  exception,  are  un- 
accompanied by  moons.  The  outer,  and,  from 
the  sun,  more  distant  planets,  are  vastly  larger, 
of  but  one-fifth  of  the  density,  more  than  twice 
as  rapid  in  their  periods  of  rotation  about  their 
axes,  flattened  towards  their  poles  in  a  much 
greater  degree,  and  attended  by  a  far  larger 
number  of  moons  ;  in  the  ratio  of  17  to  1,  if 
Uranus  have  actually  so  many  as  six  satellites. 

These  general  observations  on  certain  char- 
acteristic peculiarities  of  the  two  great  groups, 
are  not,  however,  precisely  or  in  all  respects 
applicable  to  the  particular  planets  of  each 
group  ;  for  example,  to  the  ratios  of  their  ab- 
solute magnitudes,  to  their  distances  from  the 
central  body,  to  their  densities,  to  the  times 
of  their  rotations  on  their  axes,  to  their  excen- 
tricities,  and  to  the  inclinations  of  their  orbits 
and  of  their  axes.  We  know  as  yet  of  no  in- 
timate necessity,  of  no  mechanical  natural 
law,  like  the  beautiful  law  which  connects  the 
squares  of  the  times  of  revolution  with  the 
cubes  of  the  greater  axes,  which  makes  the 
six  elements  of  the  planets  just  indicated,  and 
the  form  of  their  orbits,  dependent  on  one  an- 
other, or  on  their  mean  distances.  Mars,  more 
remote  from  the  sun,  is  smaller  than  the  Earth 
or  Venus  ;  he  approaches  Mercury — the  near- 
est of  all  the  known  planets  to  the  sun — most 
closely  in  his  diameter ;  Saturn,  again,  is  small- 
er than  Jupiter,  yet  much  larger  than  Uranus. 
The  zone  of  the  telescopic  planets,  so  insignif- 
icant in  point  of  volume,  lies,  in  a  series  of 
distances  setting  out  from  the  sun,  immediate- 
ly before  Jupiter,  the  most  considerable  of  all 
the  planetary  bodies  ;  and  yet  these  asteroids, 
several  of  whose  discs  can  scarcely  be  meas- 
ured, are  barely  one  half  more  in  their  super- 
ficies than  France,  or  Madagascar,  or  Borneo. 
Again,  however  remarkable  the  very  small 
density  of  all  the  colossal  planets  that  lie  far- 
thest from  the  sun,  there  is  still  nothing  like  a 
regular  sequence  among  them(8).  Uranus  ap- 
pears to  be  more  dense  than  Saturn,  even  when 
Lament's  smaller  mass,  ^y^o  J'  ^s  adopted ;  and 
although  the  differences  "in  point  of  density  of 
the  inner  group  of  planets  (^),  are  insignificant, 
we  still  find  Venus  and  Mars,  on  either  side  of 
the  Earth,  of  less  density  than  itself  The 
time  of  rotation  decreases,  it  is  true,  with  the 
distance  from  the  sun ;  but  for  Mars  it  is  rel- 
atively greater  than  for  the  Earth,  and  for  Sat- 
urn it  is  greater  than  for  Jupiter.  The  greatest 
excentricities  in  the  elliptical  orbits  of  any  of 
the  planets,  occur  in  those  of  Juno,  Pallas,  and 
Mercury  ;  the  least  in  those  of  Venus  and  the 


39 


THE  PLANETS.— THE  SATELLITES. 


Earth,  the  two  planets  which  follow  each  other 
immediately.  Mercury  and  Venus  present  the 
same  contrast  in  the  excentricity  of  their  orbits 
which  we  observe  in  the  four  so  closely  allied 
asteroids.  The  excentricities  of  Juno  and  Pal- 
las, which  are  very  nearly  alike,  are  three  times 
greater  than  those  of  Ceres  and  Vesta.  It  is 
the  same  with  reference  to  the  inclination  of 
the  planetary  orbits  to  the  plane  of  projection 
of  the  ecliptic,  and  to  the  position  of  the  axes 
of  rotation  on  their  orbits,  this  position  influ- 
encing climate,  season,  and  length  of  day,  still 
more  than  excentricity.  The  planets  which 
have  the  most  elongated  elliptical  orbits,  Juno, 
Pallas,  and  Mercury,  are  also  inclined  in  the 
greatest  degree,  although  not  in  equal  meas- 
ure, to  the  ecliptic.  The  orbit  of  Pallas  is  al- 
most comet-like,  and  its  inclination  is  nearly 
twenty-six  times  greater  than  that  of  Jupiter  ; 
while  the  orbit  of  the  little  Vesta,  which  is  so 
near  to  Pallas,  scarcely  exceeds  the  angle  of 
inclination  of  the  orbit  of  Jupiter  six  times. 
The  positions  of  the  axes  of  the  four  or  five 
planets,  whose  axes  of  rotation  are  known  with 
any  degree  of  certainty,  also  offer  nothing  like 
regularity  of  series.  Judging  from  the  position 
of  Uranus's  satellites,  two  of  which  (the  2d 
and  4th)  have  recently  been  certainly  seen 
again,  we  should  say,  that  the  axis  of  Uranus, 
the  outermost  of  all  the  planets,  was  scarcely 
inclined  11°  to  the  plane  of  his  orbit ;  but  Sat- 
urn, whose  axis  of  rotation  almost  coincides 
with  the  plane  of  his  orbit,  revolves  between 
Jupiter,  whose  axis  is  nearly  perpendicular,  and 
Uranus,  where,  as  we  have  seen,  it  is  but  little 
inclined. 

The  world  of  planetary  formations,  in  this 
brief  enumeration  of  the  relations  of  these  bod- 
ies in  space,  is  assumed  as  a  fact,  as  a  thing 
that  exists  in  nature,  not  as  an  object  of  intel- 
lectual intuition,  of  internal  causally-founded 
concatenation.  The  planetary  system,  in  its 
relations  of  absolute  magnitude  and  relative 
position  of  axis,  of  density,  time  of  rotation, 
and  different  degree  of  excentricity  of  orbit, 
does  not  strike  us  as  naturally  more  necessary, 
than  is  the  measure  of  separation  between  the 
land  and  the  sea  on  the  surface  of  our  planet, 
than  are  the  outlines  of  its  continents,  or  the 
heights  of  its  mountain-chains.  In  this  respect 
there  is  no  general  law  discoverable  either  in 
celestial  space,  or  in  the  inequalities  of  our 
earth's  surface.  The  things  that  we  meet  with 
are  facts  in  nature,  which  have  proceeded  from 
the  conflict  of  multifarious  forces  in  operation 
under  former  and  unknown  conditions.  But  in 
formation  ofthe  planets,  man  sees  as  accident- 
al what  he  is  incapable  of  explaining  genetical- 
ly. If  the  planets  have  been  formed  out  of 
separate  rings  of  vaporous  matter  circulating 
round  the  sun,  differences  in  the  density,  the 
temperature,  and  the  electro-magnetic  tension 
of  these  rings,  may  have  given  rise  to  the  most 
diverse  fashions  of  the  conglobated  matter ;  in 
the  same  way  as  the  amount  of  the  velocity  of 
projection,  and  trifling  aberrations  in  the  direc- 
tion of  the  projection,  may  have  given  rise  to 
manifold  forms  and  inclinations  of  the  elliptical 
Dibits.  The  attraction  of  masses,  and  the  laws 
of  gravitation,  have  undoubtedly  been  at  work 
here,  as  in  the  geognostic  relations  of  conti- 
nental upheavings ;  but  we  are  not  to  draw 


conclusions  from  the  present  state  of  things, 
as  to  the  entire  series  of  conditions  which  have 
been  passed  through  from  their  commence- 
ment. Even  the  law,  as  it  has  been  styled,  of 
the  distances  of  the  planets  from  the  sun,  the 
progression  from  the  failing  member  in  which 
Kepler  was  led  to  suspect  the  existence  of  a 
planet  betwixt  Mars  and  Jupiter,  has  been  found 
incorrect  numerically  for  the  distances  between 
Mercury,  Venus,  and  the  Earth,  and  because 
of  a  supposed  first  member,  inapplicable  to  the 
idea  of  a  regular  series. 

The  eleven  principal  planets  which  have  been 
discovered  circulating  round  the  sun,  are  ac- 
companied by  at  least  fourteen,  and  very  prob- 
ably by  eighteen,  secondary  planets  (satellites 
or  moons).  The  primary  planets  are  therefore, 
in  their  turn,  central  bodies  with  reference  to 
subordinate  systems.  And  here,  in  the  struc- 
ture of  the  universe,  we  recognize  the  same 
formative  process  which  the  evolution  of  or- 
ganic life  so  often  exhibits  to  us  in  the  ex- 
tremely complex  groups  of  animals  and  plants, 
in  the  typical  repetition  of  forms  of  subordinate 
spheres.  The  secondary  planets,  or  moons,  oc- 
cur in  larger  numbers  in  the  outer  region  of  the 
planetary  system,  in  connection  with  the  three 
great  planets  that  lie  without  the  zone  formed 
by  the  four  telescopic  planets.  With  the  single 
exception  of  the  earth,  all  the  planets  within 
this  zone  are  moonless,  and  the  satellite  of  the 
earth  is  relatively  of  very  large  dimensions,  in- 
asmuch as  its  diameter  amounts  to  one-fourth 
of  that  of  the  earth ;  whilst  the  largest  of  all 
the  secondaries  known,  the  sixth  of  Saturn,  is 
not  more  perhaps  than  the  yV^'  ^"*^  ^^^  largest 
of  Jupiter's  moons,  the  third,  is  not  above  ^'^th 
the  diameter  of  its  primary.  The  planets  which 
have  the  greatest  number  of  moons  are  the 
most  remote,  and  they  are,  at  the  same  time, 
the  largest,  the  least  dense,  and  the  most  flat- 
tened at  the  poles.  The  late  measurements 
of  Madler  seem  to  indicate  Uranus  as  the  plan- 
et which  is  flattened  towards  the  poles  in  the 
greatest  degree,  ■^.^.  In  the  earth  and  her 
moon,  whose  mean  "distance  from  one  another 
amounts  to  237,000  English  miles,  the  differen- 
ces in  the  masses  and  the  diameters  of  the  two 
bodies  are  much  smaller  than  we  are  accustom- 
ed to  meet  with  them  in  the  primary  and  sec- 
ondary planets,  and  bodies  of  a  different  order 
in  the  solar  system('»).  Whilst  the  density  of 
the  earth's  satellite  is  |ths  less  than  that  ofthe 
earth  itself,  it  would  appear,  supposing  we  can 
depend  on  the  determinations  that  have  been 
come  to  on  the  magnitudes  and  the  masses  of 
the  satellites,  that  of  the  moons  which  attend 
upon  Jupiter,  the  second  is  denser  than  the  pri- 
mary planet. 

Of  the  fourteen  satellites  the  relations  of 
which  have  been  determined  with  something 
like  accuracy,  the  system  of  Saturn  presents 
instances  of  the  most  remarkable  contrast  in 
the  absolute  magnitudes  and  distances  from 
the  primary.  The  sixth  satellite  of  Saturn  is 
probably  not  much  smaller  than  Mars,  whilst 
the  earth's  moon  is  only  one-half  the  diameter 
of  this  planet.  Next  in  order,  in  point  of  vol- 
ume, to  the  two  outermost  satellites  of  Saturn 
(the  sixth  and  the  seventh),  comes  the  third 
and  brightest  of  the  moons  of  Jupiter.  On  the 
other  hand,  the  two  innermost  satellites  of  Sat- 


SATELLITES,  OR  MOONS. 


S3 


cm,  which  were  discovered  by  Sir  William 
Herschel,  in  1789,  with  his  great  40  foot  tele- 
scope, and  which  have  been  again  seen  by  Sir 
John  Herschel  at  the  Cape,  by  Vico  at  Rome, 
and  by  Lamont  at  Munich,  belong,  in  common 
with  the  satellites  of  Uranus,  to  the  smallest  of 
the  visible  bodies  that  enter  into  the  constitu- 
tion of  our  solar  system.  These  satellites,  in- 
deed, are  only  to  be  seen  under  peculiarly  fa- 
vourable circumstances,  and  with  the  most 
powerful  telescopes.  All  determinations  of 
the  true  diameters  of  satellites,  deductions  of 
these  from  measurements  of  the  apparent  mag- 
nitudes of  small  discs,  are  exposed  to  many 
optical  difficulties  ;  and  physical  astronomy, 
wliich  calculates  before-hand,  and  with  such 
admirable  precision,  the  motions  of  the  heav- 
enly bodies,  as  they  are  exhibited  from  our 
place  of  observation,  the  earth,  is  more  con- 
cerned about  motion  and  mass,  than  volume. 

The  absolute  distance  of  a  satellite  from  its 
primary,  is  greatest  in  the  case  of  the  outer- 
most or  seventh  satellite  of  Saturn,  which  is 
half  a  million  of  geographical  miles*  remote, 
or  ten  times  as  far  as  the  distance  of  our  moon 
from  the  earth.  In  reference  to  Jupiter,  the 
outermost  or  fourth  satellite  is  ito  more  than 
260,000  geographical  miles*  from  the  planet ; 
the  fifth  satellite  of  Uranus,  however,  if  it  actu- 
ally exist,  must  be  at  the  distance  of  340,000 
miles. 

On  comparing,  in  each  of  these  subordinate 
systems,  the  volume  of  the  primary  planet,  with 
the  distance  of  the  farthest  orbit  in  which  a  sat- 
ellite has  been  formed,  we  discover  totally  dis- 
similar numerical  relations.  Expressed  in  sem- 
idiameters  of  the  principal  planets,  the  dis- 
tances of  the  farthest  satellites  of  Uranus,  Sat- 
urn, and  Jupiter,  are  as  91,  64,  and  27.  Sat- 
urn's outermost  satelMte,  therefore,  is  but  a 
very  little  (y'^th)  more  remote  from  the  centre 
of  the  primary  than  our  moon  is  from  the  earth. 
The  satellite  that  approaches  its  primary  most 
closely,  is  undoubtedly  the  first  or  innermost 
of  Saturn,  which,  in  addition,  presents  the  only 
instance  of  a  revolution  in  less  than  24  hours. 
The  distance  of  this  satellite  from  Saturn's  cen- 
tre, according  to  Madler  and  Beer,  expressed  in 
semidiameters  of  the  primary,  is  only  2-47,  or 
20,022  geographical  miles.*  Thi^ satellite  can- 
not, therefore,  be  distant  from  the  surface  of 
its  primary  more  than  11,870  g.  miles;  and 
from  the  outer  adge  of  the  ring,  only  1,229  g. 
miles.  One  who  has  been  a  traveller  readily 
forms  an  idea  of  so  short  a  distance,  the  more 
so  when  he  thinks  of  that  bold  seaman.  Captain 
Beechey,  having  sailed  over  18,200  geographi- 
cal miles  in  the  course  of  three  years.  Recur- 
ring to  semidiameters  of  the  primary  as  meas- 
ures of  distance,  we  find  that  the  first  or  inner- 
most satellite  of  Jupiter  is  no  more  than  six 
semidiameters  of  the  planet  from  his  centre  ; 
our  moon,  on  the  contrary,  is  60J  semidiame- 
ters of  the  earth  from  its  centre.  The  first  sat- 
ellite of  Jupiter  is,  nevertheless,  6,500  miles  far- 
ther from  his  centre,  than  our  moon  from  the 
centre  of  the  earth. 

In  the  subordinate  systems  of  the  satellites, 
m  other  respects,  all  the  laws  of  gravitation  are 
reflected  that  have  been  established  in  connec- 

*  The  miles  are  always  German  geographical  miles,  15 
to  a  degree  of  the  Equator.— Tbanslatok. 


tion  with  the  sun  and  the  primaries  which  re- 
volve around  him.  The  twelve  satellites  of 
Saturn,  Jupiter,  and  the  Earth,  all  revolve,  like 
the  primary  planets,  from  west  to  east,  and  in 
elliptical  orbits,  which  diflfer  but  little  from  cir- 
cles. It  is  only  the  moon,  and  probably  the 
first,  or  innermost  satellite  of  Saturn  (0  068), 
which  have  orbits,  whose  eccentricity  surpass- 
es that  of  Jupiter.  Bessel's  very  accurate  ob- 
servations on  the  6th  satellite  of  Saturn  show- 
that  the  excentricity  here  (0  029),  exceeds  that 
of  the  Earth. 

It  is  only  in  connection  with  the  satellites  of 
Uranus,  on  the  extreme  limit  of  the  planetary 
system,  at  nineteen  times  the  distance  of  the 
earth  from  the  sun,  and  where  his  central  force 
must  be  notably  diminished,  that  we  find  any 
thing  like  contrasts  to  admitted  laws.  Instead 
of  moving,  like  all  the  other  satellites,  in  or- 
bits but  little  inclined  to  the  ecliptic,  and  from 
west  to  east,  (the  ring  of  Saturn,  a  kind  of  fused 
or  undivided  satellite,  not  excepted),  the  moons 
of  Uranus  revolve  in  planes  nearly  perpendic- 
ular to  the  ecliptic,  and,  as  Sir  John  Herschel 
has  found,  after  many  years  of  observation,  in 
retrograde  courses  from  east  to  west.  If  the 
primary  and  secondary  planets  of  our  system 
have  actually  been  formed  out  of  rotating  rings 
of  vapour,  by  condensations  of  former  solar 
and  planetary  atmospheres,  there  must  have 
been  strange,  and  to  us  altogikher  inconceiva- 
ble conditions  of  retardation  or  counteraction 
among  the  vaporous  rings  that  revolved  around 
Uranus,  to  have  brought  about  such  a  singular 
opposition  to  the  motions  of  the  central  body 
as  we  observe  in  his  2d  and  3d  satellites. 

It  is  highly  probable,  that  the  period  of  rota- 
tion of  all  the  satellites  is  the  same  as  their  pe- 
riod of  revolution,  so  that  they  still  keep  the 
same  side  turned  towards  their  primaries.     In- 
equalities, as  a  consequence  of  slight  variations 
in  the  revolution,  nevertheless,  occasion  oscil- 
lations of  from  6  to  8  degrees — an  apparent  li- 
bration — both  in  longitude  and  latitude.    We 
therefore  actually  see,  in  succession,  more  than 
one  half  of  the  surface  of  the  moon  ;  at  one 
time  more  of  her  eastern  and  northern,  at  an- 
other more  of  her  western  and  southern  limb. 
By  the  libration(")  the  annular  mountain  Mal- 
apert, which  the  south  pole  of  the  moon  covers 
at  times,  is  made  more  visible  to  us,  and  then 
we  obtain  a  better  view  uf  the  arctic  landscape 
around  the  mountain-crater,  Gioja,  as  also  of 
the  extensive  grey  level  near  Endymion,  which 
surpasses  the  Mare  vaporum  in  superficial  ex- 
tent.    In  spite  of  all  this,  however,  three-sev- 
enths of  the  moon's  surface  remain,  and,  un- 
less some  new  and  unexpected  cause  of  pertur- 
bation interferes,  will  ever  remain  withdrawn 
from  our  eyes.     These  cosmic  relations  remind 
us,  involuntarily,  of  a  nearly  similar  position 
of  things  in  the  intellectual  world,  in  the  prod- 
ucts of  thought,  where,  in  the  deep  investiga- 
tion of  the  dark  elaboratory  of  nature  and  the 
prime  creative  power,  there  are  alsa  regions 
turned  from  our  ken,  and  that  seem  unattaina- 
ble, though,  in  the  course  of  thousands  of  years, 
mankind  have,  from  time  to  time,  cajught  a 
glimpse  of  some  narrow  stripe  or  margin,  now 
in  a  true  and  steady,  now  in  a  more  false  and 
flickering  light. 

We  have  hitherto  regarded  the  principal  plan- 


H 


COMETS. 


ets,  their  satellites,  and  the  concentric  ring 
that  belongs  to  at  least  one  of  the*  outermost 
of  them,  as  products  of  a  projectile  force,  and 
as  connected  with  one  another  by  intimate  bonds 
of  mutual  attractions. 

We  have  still  to  speak  of  Comets,  an  innu- 
merable host,  which  revolve  around  the  sun  in 
definite  orbits,  and  from  him  derive  their  light. 
When  we  estimate  the  relative  lengths  of  the 
orbits  of  these  bodies,  the  boundaries  of  their 
perihelia,  and  the  great  likelihood  of  their  re- 
maining invisible  to  the  inhabitants  of  the  earth, 
by  the  rule  of  probabilities,  we  find  that  they 
must  amount  to  such  myriads  as  makes  the 
imagination  pause  amazed.  Kepler,  with  the 
liveliness  of  expression  that  distinguished  him, 
says,  that  there  are  more  comets  in  the  depths 
of  space,  than  there  are  fishes  in  the  bosom  of 
the  ocean  ;  and  yet  we  have  scarcely  the  ac- 
curately-computed orbits  of  some  150  of  the 
six  or  seven  hundred  of  these  bodies,  upon 
whose  appearance  and  course  through  known 
constellations  we  have  indications  more  or  less 
rude.  Whilst  the  classic  nations  of  the  west, 
the  Ancient  Greeks  and  Romans,  occasionally 
give  the  place  in  the  heavens  where  a  comet 
was  first  seen,  but  never  say  a  word  of  its  ap- 
parent course,  the  ample  literature  of  the  Chi- 
nese, those  accurate  observers  of  nature  and 
of  individual  things,  contains  circumstantial  no- 
tices of  the  coRfitellations  through  which  each 
comet  passed.  These  notices  extend  to  more 
than  five  hundred  years  before  the  commence- 
ment of  the  Christian  era,  and  many  of  them 
are  used  by  astronomers  at  the  present  day("). 

Of  all  planetary  bodies,  comets  are  those 
which,  with  the  smallest  masses,  occupy  the 
largest  fields  of  space.  The  particular  obser- 
vations that  have  hitherto  been  made  upon 
them,  indicate  masses  much  under  the  joVo*^ 
of  that  of  the  earth  ;  yet  have  these  bodies  tails, 
which  often  extend  over  many  millions  of  miles, 
both  in  length  and  breadth.  The  light-reflect- 
ing tail,  or  cone  of  vaporous  matter  which  com- 
ets emit,  has  occasionally  been  observed  to  be 
as  long  as  is  the  distance  of  the  earth  from  the 
sun,  a  line  which  intersects  the  orbits  of  two 
of  the  planets,  those  of  Mercury  and  Venus. 
This  was  the  case  with  the  remarkable  comets 
of  1680  and  1811 ;  and  it  is  even  probable  that 
our  atmosphere  was  mingled  with  the  vapour 
of  the  comets'  tails  of  the  years  1819  and  1823. 

Comets  exhibit  such  variety  of  forms  or  ap- 
pearances, often  appertaining  to  the  individual 
rather  than  to  the  kind,  that  a  description  of 
one  of  these  travelling  light-clouds — for  so 
they  were  called  by  Xenophanes  and  Theon  of 
Alexandria,  the  contemporaries  of  Pappus — 
can  only  be  applied  with  certain  precautions  to 
another.  The  feeblest  telescopic  comets  are 
generally  without  any  visible  tail,  and  resemble 
the  nebulous  stars  of  Herschel.  They  appear 
as  rounded,  palely-glimmering  nebulae,  with  the 
light  stronger  or  more  concentrated  towards 
the  middle.  This  is  the  simplest  type  ;  but  it 
is  even  as  little  a  rudimentary  or  nascent  type 
on  this  account,  as  it  is  a  type  of  a  planetary 
body  grown  old,  and  become  exhausted  by  ex- 
halation. In  larger  comets  we  distinguish  a 
head,  or  nucleus,  as  it  is  commonly  called,  and 
a  simple  ar  compound  tail,  which  the  Chinese 
astrononaers  entitle,  very  characteristically,  the 


brush  (sui).  In  general  the  nucleus  has  no  def- 
inite outline,  although,  in  some  cases,  it  has 
the  splendour  of  a  star  of  the  first  or  second 
magnitude  ;  and  in  the  great  comets  of  1402, 
1532,  1577,  1744,  and  1843,  it  had  such  brill- 
iancy, that  it  could  be  seen  in  bright  sun- 
shine('3).  This  last  circumstance  seems  to  tes- 
tify to  the  existence,  in  some  members  of  the 
family  at  least,  of  greater  density  and  a  highly 
reflective  faculty  in  the  mass.  But  no  more 
than  two  comets  have  yet  been  seen,  which,  in 
Herschel's  great  telescope,  presented  well-de- 
fined discs(**);  these  two  are  the  one  of  1807, 
discovered  in  Sicily,  and  the  magnificent  one 
of  181 1 .  The  disc  of  the  former  appeared  under 
an  angle  of  1",  that  of  the  latter  under  an  an- 
gle of  0"-77,  from  which  an  actual  diameter  of 
134  and  107  miles  respectively  is  obtained.  The 
less  precisely  defined  nuclei  of  the  comets  of 
1798  and  1805,  indicated  diameters  of  no  more 
than  6  or  7  miles.  In  several  comets  that  have 
been  accurately  observed,  particularly  in  the 
one  of  1811,  mentioned  above,  and  that  was 
seen  so  long,  the  nucleus,  and  the  misty  en- 
velope which  surrounded  it,  were  wholly  sep- 
arated from  the  tail  by  a  darker  space.  The 
intensity  of  the  light  of  the  nucleus  does  not  go 
on  increasing  continuously  towards  the  centre  ; 
bright  zones  are  repeatedly  separated  by  con- 
centric misty  envelopes.  The  tail,  as  stated, 
has  appeared  now  single,  now  double  ;  but  rare- 
ly, although  this  was  the  case  in  the  comets  of 
1809  and  1843,  of  very  different  lengths  in  the 
two  branches;  one  comet,  that  of  1744,  has 
appeared,  which  had  six  tails.  The  tail,  again, 
is  either  straight  or  curved,  now  to  both  sides, 
now  outwardly  (1811),  or  convex  to  the  side 
towards  which  the  comet  is  tending  (1618) ; 
occasionally  the  tail  has  been  waving  or  flame- 
shaped.  The  tails  of  tomets  are  always  turn- 
ed from  the  sun  in  such  wise  that  their  axes 
produced  would  pass  through  the  centre  of  that 
luminary;  a  fact  which  Biot  assures  us  was 
notified  by  the  Chinese  astronomers  so  long 
ago  as  the  year  837,  but  which  was  first  dis- 
tinctly mentioned  in  Europe  by  Fracastorius 
and  Petrus  Apianus  in  the  16th  century.  These 
effusions  may  be  regarded  as  conoidal  enve- 
lopes, having  thicker  or  thinner  walls — a  view 
upon  which  several  very  remarkable  optical  ap- 
pearances may  readily  be  explained. 

The  several  comets,  however,  are  not  so 
characteristically  distinguished  by  their  mere 
forms  or  appearance — they  are  not  in  one  case 
tailless,  in  another  provided  with  a  tail  of  104 
degrees  in  length,  as  was  the  third  of  the  yeai 
1618;  we  further  observe  them  passing  through 
a  rapid  succession  of  varying  formative  pro- 
cesses. This  change  of  form  was  most  accu- 
rately and  ably  observed  by  Heinsius,  of  St. 
Petersburgh,  in  the  comet  of  1744,  and  in  Hal- 
ley's  comet,  on  its  last  appearance  in  1835,  by 
Bessel,  of  Konigsberg,  by  whom  it  has  been 
very  carefully  described.  On  the  part  of  the 
nucleus  which  was  turned  towards  the  sun 
there  was  a  kind  of  tufted  emanation  apparent. 
The  rays  of  this  that  bent  backwards  went  to 
form  part  of  the  tail.  "  The  nucleus  of  Halley's 
comet,  with  its  emanations,  presented  the  ap- 
pearance of  a  burning  rocket,  the  train  of  which 
was  deflected  sideways  by  a  current  of  air." 
The  rays  proceeding  from  the  head  were  seen 


COMETS. 


%5 


by  Arago  and  myself  from  the  Parisian  observ- 
atory on  successive  nights  with  very  different 
appearances(").  The  great  Konigsberg  astron- 
omer, from  numerous  measurements  and  theo- 
retical considerations,  concluded  "  that  the 
outstreaming  cone  of  light  departed  distinctly, 
both  to  the  right  and  left,  from  the  line  of  di- 
rection towards  the  sun  ;  but  always  returned 
to  this  line  again,  to  pass  over  to  the  opposite 
side ;  that  the  outstreaming  cone  of  light, 
therefore,  as  well  as  the  body  of  the  comet  it- 
self, which  engenders  and  throws  it  out,  has  a 
rotatory,  or  rather  a  vibratory  motion  in  the 
plane  of  the  orbit."  He  found,  further,  "that 
the  ordinary  attractive  force  of  the  sun  which  is 
exerted  upon  heavy  bodies,  is  not  adequate  to  ac- 
count for  these  vibrations;"  and  is  of  opinion 
*'  that  they  proclaim  a  power  of  polarity  in  the 
comet,  which  keeps  one  semidiameter  of  the 
body  turned  towards,  the  other  semidiameter 
turned  from,  the  sun ;  that  the  magnetic  proper- 
ty possessed  by  the  earth  may  present  some- 
thing of  an  analogous  nature  ;  and  should  the  op- 
posites  of  the  telluric  polarity  inhere  in  the  sun, 
the  influence  of  this  might  show  itself  in  the 
precession  of  the  equinoxes."  This  is  not  the 
place  for  a  more  particular  development  of  the 
grounds  upon  which  explanations  that  accord 
with  the  phenomena  have  been  built ;  but  ob- 
servations so  remarkable("),  views  of  such 
magnitude  in  reference  to  the  most  wonderful 
class  of  bodies  that  belong  to  our  solar  system, 
could  not  be  passed  by  unnoticed  in  this  sketch 
of  a  general  picture  of  nature. 

Notwithstanding  the  rule  according  to  which 
the  tails  of  comets  increase  in  size  an^^  bright- 
ness as  the  perihelion  is  approach^,  and  are 
turned  from  the  central  body  of  our  system, 
the  comet  of  1823  presented  Ae  remarkable 
example  of  two  tails,  which  ^rmed  an  angle  of 
160°  with  each  other,  and  of  which  one  was 
turned  from  the  sun,  as  usual,  whilst  the  oth- 
er was  turned  towards  him.  Peculiar  modifi- 
cations of  the  polarity,  and  unequal  distribu- 
tion and  condu(x;ion  of  this,  may,  in  the  rare 
instance  just  quoted,  have  occasioned  a  two- 
fold  and   uninterrupted  effusion  of  nebulous 

matter(»0 

In  the  natural  philosophy  of  Aristotle,  the 
phenomena  of  comets  and  the  existence  of  the 
milky  way  may  be  brought  into  a  most  strange 
juxtaposition  or  connection.  The  countless 
multitude  of  stars  which  compose  the  milky 
way  give  off  a  self-igniting  or  luminous  mass  ; 
and  the  nebulous  streak  that  divides  the  vault 
of  the  heavens  is  therefore  regarded  by  the 
Stagirite  as  a  mighty  comet,  which  ceaseless- 
ly reproduces  itself(^^). 

Occultations  of  the  fixed  stars  by  the  head 
or  nucleus  of  a  comet,  or  its  immediate  vapor- 
ous envelope,  might  throw  some  light  upon  the 
physical  constitution  of  these  wonderful  heav- 
enly bodies  ;  but  we  have  no  observations 
which  give  us  unquestionable  assurance  that 
any  occultation  has  been  observed  which  was 
completely  central(i') ;  for,  as  we  have  above 
observed,  there  are  alternate  concentric  scales 
of  dense  and  very  rare  vapour  in  the  parts  ly- 
ing near  the  nucleus.  On  the  other  hand, 
there  is  no  question  of  the  fact,  that  on  the 
29th  of  September,  1835,  the  light  of  a  star  of 
the  10th  magnitude  passed  through  an  extreme- 


ly dense  vapour,  at  the  distance  of  7"78  from 
the  central  point  in  the  head  of  Halley's  com- 
et, according  to  Bessel's  very  accurate  meas- 
urements ;  and  that  the  light  of  this  star  suf- 
fered not  the  slightest  deflection  from  its  rec- 
tilinear course  at  any  moment  of  the  passage 
through  this  vapour^"*).  Such  an  absence  of 
refractive  power,  if  it  actually  extends  to  the 
centre  of  the  nucleus,  renders  it  difficult  to  im- 
agine that  the  matter  of  comets  is  at  all  of  the 
nature  of  a  gasiform  fluid.  Or,  is  the  absence 
of  refringent  power  the  mere  result  of  an  almost 
infinite  rarity  of  a  fluid  of  this  description'?  or 
does  a  comet  consist  of  segregated  particles, 
forming  a  cosmic  cloud,  which  affects  the  ray 
of  light  passing  through  it  in  no  greater  degree 
than  the  clouds  of  our  atmosphere,  which  have 
no  influence  in  altering  the  zenith  distance  of 
the  fixed  stars  or  the  edges  of  the  suni  A 
greater  or  less  diminution  of  the  light  of  a  fixed 
star  has  indeed  been  remarked  during  the  pas- 
sage of  a  comet  over  it,  but  this  has  been  as- 
cribed, with  great  propriety,  to  the  lighter 
ground  from  which  the  star  appears  to  stand 
out  during  the  occultation. 

The  most  important  and  decisive  observa- 
tions which  have  yet  been  made  upon  the  na- 
ture of  the  light  of  comets,  are  those  of  Arago 
on  its  polarization.  The  polariscope  of  this 
distinguislied  philosopher  gives  us  information 
of  the  physical  constitution  of  the  sun  as  well 
as  orthat  of  comets  ;  the  instrument,  in  a  word, 
informs  us  whether  a  ray  of  light  that  reaches 
us  after  travelling  many  millions  of  miles,  is 
direct  or  reflected  light,  and  whether,  in  the 
former  case,  the  source  of  the  ray  is  a  solid,  a 
liquid,  or  a  gaseous  body.  The  light  of  Capel- 
la,  and  that  of  the  great  comet  of  1819,  were 
examined  by  the  same  apparatus :  the  comet 
showed  polarized  and  therefore  reflected  light ; 
the  brilliant  star,  as  was  to  have  been  antici- 
pated, proclaimed  itself  a  self-luminous  sun(=^). 
The  existence  of  polarized  light  in  connection 
with  the  comet,  however,  was  not  merely  made 
known  by  the  inequality  of  the  images ;  on  the 
reappearance  of  Halley's  comet  in  the  year 
1835,  it  was  still  more  distinctly  indicated  by 
the  striking  contrast  of  complementary  colours, 
in  accordance  with  the  laws  of  chromatic  po- 
larization discovered  by  Arago,  in  1811.  But 
it  still  remains  undetermined,  even  by  the  beau- 
tiful experiments  just  referred  to,  whether,  be- 
sides the  reflected  sun-light,  comets  have  not 
also  a  light  proper  to  themselves.  In  some,  at 
least,  of  the  true  planets,  Venus  for  example, 
it  appears  to  be  extremely  probable  that  there 
is  an  inherent  independent  capacity  to  evolve 
light. 

The  variable  brightness  of  comets  is  not  al- 
ways to  be  explained  from  their  position  in 
their  orbit,  and  their  distance  from  the  sun.  It 
certainly  points,  in  particular  individuals,  to 
internal  processes  of  condensation,  and  of  aug- 
mented or  diminished  power  of  reflecting  bor- 
rowed light.  In  the  case  of  the  comet  of  1618, 
as  also  of  the  one  with  a  period  of  three  years, 
Hevelius  observed  the  nucleus  to  be  lessened 
as  the  sun  was  approached,  increased  as  he 
was  quitted ;  and  this  remarkable  phenomenon, 
so  long  neglected,  has  lately  been  again  refer- 
red to  and  confirmed  by  Balz,  the  able  astrono- 
mer of  Nismes.    The  regularity  in  the  altera- 


36 


COMETS. 


lion  of  volume  according  to  the  distance  from 
the  sun  is  particularly  striking.  The  physical 
explanation  of  the  phenomenon  cannot  well  be 
sought  for  in  any  increased  density  of  the  lay- 
ers of  the  world-ether  at  distances  progressive- 
ly nearer  the  sun  ;  for  it  is  difficult  to  conceive 
the  vaporous  envelope  of  the  comet's  nucleus 
as  vesicular,  and  impenetrable  to  the  ether  that 
fills  the  universe("). 

The  very  dissimilar  excentricities  in  the  el- 
liptical orbits  of  comets  has  led  in  recent  times 
(1819)  to  brilliant  additions  to  our  knowledge 
of  the  solar  system.  Encke  made  the  discov- 
ery of  a  comet  of  so  short  a  period  that  it  always 
remains  within  the  limits  of  our  planetary  or- 
bits ;  he  found  that  the  place  of  its  aphelion  or 
greatest  distance  from  the  sun  lay  between  the 
orbits  of  the  telescopic  planets  and  that  of  Ju- 
piter. The  excentricity  of  this  comet's  orbit  is 
0-845,  that  of  Juno  (the  greatest  excentricity 
among  all  the  planetary  orbits)  being  0  255. 
Encke's  comet  has  repeatedly  been  seen  with 
the  naked  eye,  although  it  is  not  easily  discov- 
ered ;  it  was  seen,  however,  in  Europe  in  1819, 
and,  according  to  Riimker,  in  New  Holland  in 
1823.  The  period  of  this  comet  is  nearly  3| 
years ;  but  from  careful  comparisons  of  the 
times  of  its  return  to  the  perihelion,  the  remark- 
able fact  has  been  discovered  that  its  periods 
from  1786  to  1838  have  been  going  on  regularly 
contracting  from  revolution  to  revolution,  viz., 
in  the  course  of  52  years,  by  one  and  f'oths  of 
a  day.  So  remarkable  a  circumstance  has  led 
to  the  admission  of  the  very  probable  existence 
of  a  vaporiform  matter  diffused  in  planetary 
space,  and  capable  of  opposing  a  certain  resist- 
ance to  bodies  in  motion  through  it.  Some- 
thing of  the  kind,  indeed,  seems  necessary  in 
order  to  bring  the  most  careful  consideration  of 
every  source  of  planetary  perturbation  into  har- 
mony with  the  results  of  observation  and  calcu- 
lation. The  tangential  force  is  diminished,  and 
A^ith  it  the  greater  axis  of  the  cometary  orbit. 
The  value  of  the  constant  of  resistance  appears, 
moreover,  to  be  somewhat  different  before  and 
after  the  passage  of  the  perihelion,  which  is 
perhaps  to  be  ascribed  to  the  altered  form  of 
the  small  nucleus,  and  to  the  effect  of  inequality 
in  density  of  the  layers  of  ether  in  the  sun's 
vicinity(^^).  These  facts,  and  their  explanation, 
must  be  reckoned  among  the  number  of  the 
most  interesting  results  of  modern  astronomy. 
And  then,  if  Encke's  comet  led  us  at  an  earlier 
period  to  subject  the  mass  of  Jupiter — always 
so  important  in  every  reckoning  of  perturbation 
— to  a  closer  scrutiny,  its  course  has  subse- 
quently obtained  for  us  the  first,  although  mere- 
ly approximative,  determination  of  an  inferior 
mass  for  Mercury. 

The  first  comet  of  short  period,  namely, 
Encke's,  of  3^  years,  was  followed,  in  1826,  by 
another  planetary  one,  the  aphelion  of  which 
lies  beyond  the  orbit  of  Jupiter,  but  much  within 
that  of  Saturn.  This,  or  Biela's  comet,  com- 
pletes its  revolution  in  6|  years.  Its  light  is 
still  more  feeble  than  that  of  Encke's  comet. 
The  motion  of  both  these  comets  is  direct, 
whilst  that  of  Halley's  is  retrograde — contrary 
to  the  motion  of  the  planets  properly  so  called. 

Biela's  comet  presents  the  first  certain  in- 
stance of  the  orbit  of  a  comet  intersecting  that 
of  the  Earth ;  its  path  is,  therefore,  one  of  pos- 


sible danger — if  we  can  regard  as  dangero«ir  a 
phenomenon  which  has  not  been  observed  within 
the  historical  period,  and  of  which  the  conse- 
quences are  doubtful.  Small  masses,  possess- 
ed of  enormous  velocities,  may  certainly  exei- 
cise  a  notable  force ;  but,  though  Laplace  de- 
monstrated the  mass  of  the  comet 'of  1770  to 
be  less  than  the  l-5000th  of  that  of  the  Earth, 
he  supposes,  with  a  certain  degree  of  probabil- 
ity, that  the  average  masses  of  the  comets  are 
much  below  the  one  hundred  thousandth  part 
of  the  Earth's  (about  the  l-1200th  of  the  moon's; 
mass(").  We  must  not  confound  the  passage 
of  Biela's  comet  through  our  earth's  orbit,  with 
its  proximity  to,  or  absolute  encounter  with  the 
Earth  itself  When  this  passage  took  place  on 
October  29th,  1832,  the  Earth  was  still  a  full 
month  off  from  the  point  of  intersection  of  the 
two  orbits. 

The  orbits  of  these  two  comets  of  short  pe- 
riod mutually  intersect  each  other ;  and  it  ha.s 
been  correctly  observed("*),  that  owing  to  the  nu- 
merous perturbations  which  such  small  celestial 
bodies  suffer  from  the  planets,  it  is  not  impos- 
sible for  them  to  encounter,  and  that,  should 
this  occur  about  the  middle  of  the  month  oi 
October,  the  inhabitants  of  the  Earth  might  be- 
hold  the  extraordinary  spectacle  of  a  cosmicat 
combat ;  in  other  words,  of  the  mutual  pene- 
tration of  two  comets,  of  their  agglutination,  or 
of  their  destruction,  in  consequence  of  exhaust- 
ive emanations.  The  immense  ethereal  ex- 
panse may  have  witnessed  during  millions  of 
years  several  events  of  this  kind,  consequences 
of  deviations  produced  by  perturbing  masses, 
or  of  originally  intersecting  orbits ;  still  the) 
are  insulated  phenomena,  having  as  little  gen- 
eral influence  in  modifying  the  form  or  state  oi 
the  universt,  as  the  appearance* or  extinction 
of  a  volcano  Ik  the  limited  sphere  of  the  Earth. 

A  third  planetary  comet  of  short  period  was 
discovered  by  Fayt  on  November  22d,  1843,  at 
the  Paris  Observator/  Its  elliptical  orbit  ap- 
proximates more  nearly  Vo  a  circle  than  that  of 
any  other  known  comet,  za\d  is  included  be- 
tween the  paths  of  Mars  ar.d  Saturn.  Tliis 
comet  (which  Goldschmidt  say&  stretches  be- 
yond the  orbit  of  Jupiter),  is  theiefore  one  of 
the  few  known  which  has  its  perihelion  oeyond 
the  orbit  of  Mars.  It  accomplishes  its  revolu- 
tion in  7-29  years,  and  probably  owes  the  pres- 
ent form  of  its  orbit  to  its  great  proximity  to 
Jupiter  at  the  close  of  1839. 

When  we  consider  comets  in  their  closed 
elliptical  orbits  as  members  of  our  solar  system, 
with  reference  to  their  major  axes,  their  ex- 
centricities, and  their  periods  of  revolution,  it 
seems  probable  that  in  the  last  particular  the 
three  planetary  comets  (Encke's,  Biela's,  and 
Faye's)  are  immediately  succeeded  by  Messier's 
of  1766  (supposed  by  Clausen  to  be  identical 
with  the  third  comet  of  1819),  and  by  the  fourth 
of  1819,  discovered  by  Blanpain,  which  Clausen 
considers  identical  with  that  of  1743,  but  which, 
as  well  as  Lexell's,  has  suffered  great  orbital 
changes  from  the  proximity  and  attraction  of 
Jupiter.  These  two  comets  appear  to  have  a 
period  of  from  five  to  six  years,  and  their  aphe- 
lia  fall  in  the  neighbourhood  of  the  orbit  of  Ju- 
piter. From  70  to  76  years  are  occupied  in 
their  revolutions,  by  Halley's  comet  (so  impor- 
tant in  a  theoretical  point  of  view,  of  which 


COMETS. 


the  last  appearance,  in  1835,  was  less  brilliant 
than  its  former  ones  had  led  astronomers  to 
expect  it  would  prove),  by  Olbers's  comet  of 
March  6,  1815,  and  by  Pons's  comet  of  1812, 
the  elements  of  which  were  calculated  by 
Encke.  Both  of  the  latter  were  invisible  to 
the  naked  eye.  The  great  comet  of  Halley  has 
already  greeted  us  for  the  ninth  known  time ; 
Laugier's  computations^)  having  recently  de- 
monstrated that  it  is  identical  with  the  comet 
of  1378,  recorded  in  Ed.  Biot's  Chinese  Cata- 
logue of  Comets.  From  1378  to  1835  its  period 
lias  varied  between  7491  and  77-58  years,  the 
mean  having  been  seventy-six  years. 

Contrasted  with  the  celestial  bodies  above 
mentioned,  we  behold  another  series  of  bodies 
requiring  millenniums  for  their  barely  determi- 
nable periods.  Thus,  Argelander  says  that  the 
splendid  comet  of  1811  requires  3065  years  for 
its  revolution,  whilst  Encke  fixes  8800  years  for 
the  awfully  grand  one  of  1680.  These  bodies, 
therefore,  recede  respectively  21  and  44  times 
farther  from  the  Sun  than  Uranus ;  that  is, 
8400  and  17,600  millions  of  miles.  The  Sun's 
attractive  force  extends  therefore  even  to  this 
enormous  distance  ;  but  then,  whilst  the  comet 
of  1680,  at  its  perihelion,  travels  at  the  rate  of 
53  miles  (above  1,300,000  English  feet)  per  sec- 
ond, or  13  times  faster  than  the  Earth,  its  ve- 
locity hardly  attains  10  8  E.  feet  per  second  at 
its  aphelion.  The  last-mentioned  rate  is  only 
thrice  greater  than  the  velocity  of  water  in  our 
most  sluggish  European  rivers,  and  but  half 
the  velocity  which  I  observed  in  the  Cassi- 
quiare,  a  branch  of  the  Orinoko.  Amongst  the 
immense  number  of  uncomputed  or  undiscov- 
ered comets,  there  are  most  probably  many 
which  have  a  major  orbital  axis  far  exceeding 
that  of  the  comet  of  1680.  In  order  to  give 
some  idea,  if  not  of  the  extent  of  the  sphere  of 
attraction,  at  least  of  the  spacial  distance  of  a 
fixed  star,  or  other  sun,  from  the  aphelion  of 
the  comet  of  1680  (the  most  distant  traveller 
of  all  the  celestial  bodies  of  our  system,  ac- 
cording to  our  present  knowledge),  I  need  only 
remind  the  reader  that  the  most  recent  esti- 
mates of  parallax  still  make  the  nearest  fixed 
star  250  times  farther  from  the  sun  than  the 
aphelion  of  this  comet,  which  is  only  44  times 
as  remote  as  Uranus,  whilst  the  star  a  Cen- 
tauri  is  11,000,  and  the  star  61  Cygni  (after 
Bessel's  very  accurate  observations)  is  31,000 
times  more  distant  than  the  planet. 

After  this  consideration  of  the  greatest  elon- 
gations of  comets  from  the  central  body  of  the 
solar  system,  let  us  glance  at  those  which  have 
approached  it  most  nearly.  The  instance  of 
the  greatest  known  proximity  of  a  comet  to  the 
earth  occurred  with  that  of  Lexell  and  Burk- 
hardt,  celebrated  for  the  perturbations  it  suffer- 
ed from  Jupiter ;  this  comet  was  only  six 
times  the  distance  of  the  moon  from  us  on  June 
28Lh,  1770.  In  1767  and  1779,  the  same  comet 
twice  traversed  the  system  of  Jupiter's  satel- 
lites, without  causing  the  slightest  perceptible 
derangement  in  their  orbits  ;  orbits  which  have 
been  so  thoroughly  investigated  by  physical 
astronomers.  But  the  great  comet  of  1680, 
when  at  its  perihelion,  was  from  eight  to  nine 
times  nearer  to  the  surface  of  the  sun  than 
Lexell's  was  to  the  earth.  On  December  17th, 
the  sun  and  the  comet  of  1680  were  only  one- 


sixth  of  the  diameter  of  the  former  body  apart ; 
in  other  words,  seven-tenths  of  the  moon's  dis- 
tance from  us.  Owing  to  the  feebleness  of  the 
light  of  distant  comets,  perihelia  beyond  the 
orbit  of  Mars  are  rarely  observable  by  man ; 
the  comet  of  1729  is,  in  fact,  the  only  one  of 
those  hitherto  computed  which  has  its  perihe- 
lion between  the  orbits  of  Pallas  and  Jupiter, 
and  which  has  been  observed  beyond  the  path 
of  the  latter  planet. 

Since  scientific  acquirements,  some  solid,  by 
the  side  of  much  superficial  learning,  have  pen- 
etrated in  wider  circles  into  social  life,  the 
fears  of  the  possible  evils  wherewith  comets 
threaten  us  have  increased  in  weight,  and  their 
direction  has  become  more  definite.  The  cer- 
tainty of  there  being  several  periodical  comets 
within  the  known  planetary  orbits,  visiting  us 
at  short  intervals ;  the  considerable  perturba- 
tions which  Jupiter  and  Saturn  cause  in  their 
paths,  whereby  apparently  harmless  wanderers 
of  the  sky  may  be  converted  into  peril-fraught 
bodies  ;  the  orbit  of  Biela's  comet  passing 
through  that  of  the  earth ;  the  existence  of  a 
cosmical  ether,  that  resisting  and  retarding 
fluid  which  tends  to  contract  the  orbits  of  all 
the  planetary  bodies  ;  the  individual  diflferences 
in  the  bodies  of  comets  which  permit  us  to 
suspect  considerable  gradations  in  the  quantity 
of  the  mass  of  the  nucleus ;  all  these  circum- 
stances amply  replace,  in  multiplicity  of  grounds, 
the  dread  which,  in  former  centuries,  was  en- 
tertained of  flaming  swords,  and  an  universal 
conflagration  to  be  lighted  up  by  fiery  stars. 

As  the  grounds  for  confidence  derivable  from 
the  doctrine  of  probabilities  only  operate  on  the 
understanding,  are  only  of  avail  among  the  re- 
flecting, and  produce  no  effect  on  gloomy  ap- 
prehension and  imagination,  modern  science 
has  been  charged,  not  altogether  without  rea- 
son, with  seeking  to  allay  the  fears  which  it 
has  itself  created.  It  is  a  principle  laid  deeply 
in  the  desponding  nature  of  man,  in  his  inhe- 
rent disposition  to  view  things  on  the  dark 
rather  than  on  the  bright  side,  that  the  unex- 
pected,  the  extraordinary,  excites  fear,  not 
hope  or  joy^"^).  The  strange  aspect  of  a 
mighty  comet,  its  pale  nebulous  gleam,  its  sud- 
den appearance  in  the  heavens,  have  in  all 
countries,  and  almost  at  all  times,  been  held  as 
portentous  indications  of  change  or  dissolution 
of  the  old-established  order  of  things.  And 
then,  as  the  apparition  is  never  more  than 
short  lived,  arises  the  belief  that  its  significance 
must  be  reflected  in  contemporaneous  or  im- 
mediately succeeding  events.  And  such  is  the 
enchainment  of  events,  that  some  particular 
incident  scarcely  fails  to  turn  up  which  can  be 
fixed  upon  as  the  calamity  prognosticated.  It 
is  only  in  these  times  that  a  spirit  of  greater 
hopefulness,  in  connection  with  the  appearance 
of  comets,  has  shewn  itself  among  the  people. 
In  the  beautiful  valleys  of  the  Rhine  and  the 
Moselle,  ever  since  the  appearance  of  the  brill- 
iant comet  of  1811,  comets  have  been  regarded 
as  exerting  a  favourable  influence  on  the  ripen- 
ing of  the  grape  ;  nor  have  various  years  of  in- 
different vintage,  along  with  the  appearance  of 
other  comets,  instances  of  which  have  not 
been  wanting,  been  able  to  shake  the  faith  n' 
the  wine-growers  of  the  north  of  Germany  in 
their  beneficial  influences. 


3ff 


SHOOTING  STARS  AND  AEROLITES. 


I  now  pass  from  comets  to  another  and  yet 
more  enigmatical  class  of  agglomerated  matter, 
to  the  smallest  of  all  asteroids,  which,  in  their 
fragmentary  condition,  and  when  they  have 
arrived  in  our  atmosphere,  we  designate  by 
the  name  of  Aerolites,  or  Meteoric  Stones.  If 
I  dilate  at  greater  length  on  these  bodies  than 
I  have  done  on  comets,  and  accumulate  those 
individual  features  which  should  otherwise  be 
excluded  from  a  general  survey  of  nature,  it  is 
done  with  a  purpose.  The  very  remarkable 
characteristic  diversities  of  comets  have  been 
long  known.  From  the  little  that  has  yet  been 
learned  of  their  physical  condition,  it  is  diffi- 
cult, in  an  exposition  such  as  is  here  required, 
to  seize  the  Common,  and  to  separate  the  Ne- 
cessary from  the  Accidental,  in  phenomena 
observed  with  very  difTerent  degrees  of  accu- 
racy. The  measuring  and  calculating  astron- 
omy of  comets  has  alone  made  marvellous 
progress.  In  this  state  of  our  knowledge,  a 
scientific  consideration  must  be  limited  to  phys- 
iognomical differences  in  the  fashion  of  the 
nucleus  and  tail ;  to  examples  of  close  approxi- 
mations to  other  planetary  bodies  ;  to  extremes 
in  orbits  with  reference  to  space,  and  in  pe- 
riods of  revolution  to  time.  Natural  truth  in 
these,  as  in  the  phenomena  that  are  immedi- 
ately to  be  spoken  of,  is  only  to  be  attained 
by  a  delineation  of  the  Individual,  and  by  the 
animated  and  contemplative  expression  of  re- 
ality. 

Shooting  Stars,  Fire-b.^lls,  and  Meteoric 
Stones,  are,  with  great  appearance  of  proba- 
bility, regarded  as  small  masses  moving  with 
planetary  velocity  in  conic  sections  round  the 
sun,  in  harmony  with  the  laws  of  universal 
gravitation.  When  these  masses  encounter 
the  Earth  in  their  course,  and,  attracted  by  it, 
become  luminous  on  the  verge  of  our  atmo- 
sphere, they  frequently  let  fall  stony  fragments, 
heated  in  greater  or  less  degree,  and  covered 
on  their  surface  with  a  black  and  shining  crust. 
By  careful  analysis  of  all  that  has  been  observ- 
ed at  different  epochs  when  great  numbers  of 
shooting  stars  have  fallen,  as  at  Cumana  in 
1799,  in  North  America  in  1833  and  1834,  &c., 
it  seems  no  longer  proper  to  separate  fire-balls 
from  shooting  stars.  Both  phenomena  are  not 
only  frequently  contemporaneous  aitd  inter- 
mingled, but  they  also  pass  into  one  another, 
and  this  whether  we  pay  particular  attention 
to  the  dimensions  of  the  discs,  to  the  sparks  or 
trains  of  fire  which  they  emit,  or  to  the  veloci- 
ties of  their  respective  motions.  Whilst  there 
are  fire-balls  that  have  the  apparent  diameter 
of  the  moon,  that  explode  and  emit  smoke,  and 
possess  such  brilliancy  that  they  can  be  seen 
at  noon-day(**),  there  are,  on  the  other  hand, 
shooting  stars  in  countless  multitudes,  of  such 
small  dimensions  that  they  only  present  them- 
selves to  the  eye  in  the  form  of  moving  points 
or  of  phosphorescent  linesC*').  But  whether 
or  not  among  the  many  luminous  bodies  that 
shoot  through  the  sky  in  the  form  of  falling 
stars  and  meteors,  there  are  not  several  of  dif- 
ferent natures,  remains  to  be  shown.  Occu- 
pied, shortly  after  my  return  home,  with  the 
impression  which  the  phenomena  of  shooting 
stars  had  left  upon  my  mind,  and  remembering 
that  I  had  observed  them  in  greater  numbers, 
of  brighter  colours,  and  more  commonly  ac- 


companied by  long  and  brilliant  trains,  both  on 
intertropical  plains  just  raised  above  the  level 
of  the  sea,  and  on  mountains  at  the  height  of 
twelve  and  even  fifteen  thousand  feet  above 
its  surface,  than  in  the  temperate  and  frigid 
zones,  I  soon  perceived  that  the  ground  of  the 
more  vivid  impression  lay  in  the  glorious  trans- 
parency of  the  tropical  atmosphere  itsGlf(3'>). 
There  one  sees  deeper  into  space.  Sir  Alex- 
ander Burnes,  too,  speaks  of  the  magnificent 
and  constantly  recurring  spectacle  of  coloured 
shooting  stars,  which  he  enjoyed  in  Bokhara, 
and  which  he  attributes  to  the  purity  of  the  at- 
mosphere. 

The  connection  of  meteoric  stones  with  the 
grander  and  more  brilliant  phenomena  of  fire- 
balls— that  stones  actually  fall  from  these  fire- 
balls, and  penetrate  ten  or  fifteen  feet  into  the 
ground,  has  been  shown,  among  many  other 
instances  of  the  kind,  by  the  well-known  fall 
of  aerolites  at  Barbotan,  in  the  department  Des 
Landes,  on  the  24th  July,  1790,  at  Lima  on  the 
16th  of  June,  1794,  at  Weston,  in  Connecticut, 
on  the  14th  of  December,  1807,  and  at  Juvenas, 
in  the  department  of  Ardeche,  on  the  15th  of 
June,  1821.  Other  phenomena  connected  with 
the  fall  of  aerolites  are  those  where  the  masses 
have  descended,  shaken,  as  it  were,  from  the 
bosom  of  a  small  dark  cloud,  which  had  formed 
suddenly  in  the  midst  of  a  clear  sky,  accompa- 
nied with  a  noise  that  has  been  compared  to 
the  report  of  a  single  piece  of  artillery.  Whole 
districts  of  country  have  occasionally  been  cov- 
ered with  thousands  of  fragments  of  stones, 
of  very  dissimilar  magnitudes,  but  like  consti- 
tution, which  had  been  rained  down  from  a  pro- 
gressive cloud  of  the  kind  described.  In  rarer 
instances,  as  in  that  which  occurred  at  Klein- 
wenden,  not  far  from  Miihlhausen,  on  the  16th 
of  September,  1843,  large  aerolites  have  fallen 
amidst  a  noise  like  thunder,  when  the  sky  was 
clear  and  without  the  formation  of  any  cloud. 
The  close  affinity  between  fire-balls  and  shoot- 
ing stars  is  also  shown  by  the  fact  of  instances 
having  occurred,  of  the  former  throwing  down 
stones,  though  they  had  scarcely  the  diameter 
of  the  balls  that  are  projected  from  our  fire- 
works called  Roman  candles.  This  happened 
notably  at  Angers  on  the  9th  of  June,  1822. 

With  regard  to  the  form-producing  forces, 
the  physical  and  chemical  processes  in  these 
phenomena,  we  are  still  completely  in  the  dark. 
We  know  not  whether  the  particles  which  form 
the  compact  mass  of  the  aerolite  lay  originally 
apart  from  one  another,  in  the  shape  of  vapour, 
as  in  comets,  and  first  contracted  and  ran  to- 
gether when  they  began  to  ligliten  within  the 
gleaming  ball ;  we  know  nothing  of  what  takes 
place  in  the  black  cloud,  where  it  sometimes 
continues  to  thunder  for  minutes  before  the 
stones  descend  ;  neither  are  we  aware  wheth- 
er from  the  smaller  shooting  stars  there  be  any 
precipitation  of  solid  matter,  or  only  an  attenu- 
ated dry  haze,  or  a  ferruginous  and  nickcliferous 
meteoric  dust(^').  We,  however,  know  the  im- 
mense, the  wonderful  and  perfectly  planetary 
rapidity  of  shooting  stars,  fire-balls,  and  mete- 
oric stones ;  we  recognise  the  General  in  ref- 
erence to  them,  and  in  this  Generality  perceive 
uniformity  of  phenomena  only,  nothing  of  ge- 
netical  cosmic  process,  the  consequence  of 
change.    If  meteoric  stones  revolve  already 


SHOOTING  STARS  AND  AISROLITES. 


39 


consolidated  into  dense  masses^^  (less  dense,  | 
however,  than  the  mean  density  of  the  Earth),  | 
then  must  they  form  very  insignificant  nuclei 
to  the  fire-balls,  surrounded  by  inflammable  va- 
pours or  gases,  from  the  interior  of  which  they 
shoot,  and  which,  judging  from  their  height  and 
apparent  diameters,  must  have  actual  diame- 
ters of  from  500  to  2600  feet.  The  largest  me- 
teoric masses  of  which  we  have  information, 
those  to  wit  of  Bahia  and  Otumpa  in  Chaco, 
which  Rubi  de  Celis  has  described,  are  from  7 
to  7^  feet  in  length.  The  meteoric  stone  of 
Aegog  Potamos,  so  celebrated  through  the 
whole  of  antiquity,  and  which  is  even  mention- 
ed in  the  Marble  Chronicle  of  Paris,  is  described 
as  having  been  of  the  magnitude  of  two  mill- 
stones, and  of  the  weight  of  a  wagon  load. 
Despite  the  vain  attempts  of  the  African  trav- 
eller, Browne,  I  have  not  yet  abandoned  the 
hope  that  this  great  Thracian  meteoric  stone, 
which  must  be  so  difficult  of  destruction,  though 
it  fell  more  than  2300  years  ago,  will  again  be 
discovered  by  one  or  other  of  the  numerous 
Europeans  who  now  perambulate  the  East  in 
safety.  The  enormous  aerolite  which  fell  in 
the  beginning  of  the  10th  century  in  the  river 
at  Narni,  projected  a  whole  ell  above  the  sur- 
face of  the  water,  as  we  are  assured  by  a  doc- 
ument lately  discovered  by  Pertz.  It  is  to  be 
observed,  however,  that  none  of  these  aerolites, 
whether  of  ancient  or  modern  times,  can  be  re- 
garded as  more  than  principal  fragments  of  the 
mass  which  was  scattered  by  the  explosion  of 
the  fire-ball  or  murky  cloud  whence  they  de- 
scended. 

When  we  duly  consider  the  mathematically 
determined  enormous  velocities  with  which 
meteoric  stones  fall  from  the  outer  confines  of 
our  atmosphere  to  the  earth,  or  with  which,  as 
fire-balls,  they  speed  for  long  distances  through 
even  the  denser  fields  of  air,  it  seems  to  me 
more  than  improbable  that  the  metalliferous 
mass,  with  its  internally  disseminated  and  very 
perfect  crystals  of  olivine,  labrador,  and  pyrox- 
ene, could  have  run  together  in  so  short  an  in- 
terval into  a  solid  nucleus  from  any  state  of  gas 
or  vapour.  The  mass  that  falls,  besides,  even 
in  cases  where  the  chemical  constitution  varies, 
has  always  the  particular  characters  of  a  frag- 
ment ;  it  is  commonly  of  a  prismatoidal  or  ir- 
regular pyramidal  form,  with  somewhat  arched 
surfaces  and  round  edges.  But  whence  this 
figure,  first  observed  by  Schreibers,  of  a  mass 
detached  from  a  rotating  planetary  body  1  Hgre, 
too,  as  in  the  circle  of  organic  life,  all  that  has 
reference  to  the  history  of  evolution  is  hidden 
in  obscurity.  Meteors  begin  to  lighten  and  to 
burn  at  elevations  which  we  must  look  upon  as 
almost  perfect  vacuums,  or  that  cannot  contain 
l-100,000th  of  oxygen.  Biot's  new  researches 
on  the  interesting  crepuscular  phenomenon(23), 
reduce  the  line  very  notably  which,  somewhat 
hardily  perhaps,  is  frequently  spoken  of  as  the 
limits  of  our  atmosphere ;  but  luminous  phe- 
nomena take  place  independently  of  the  pres- 
ence of  oxygen,  and  Poisson  has  admitted  the 
combustion  of  aerolites,  or  meteors,  as  occur- 
ring far  beyond  the  confines  of  our  atmosphere. 
It  is  only  in  so  far  as  calculation  and  geomet- 
rical admeasurement  can  be  applied  to  meteor- 
ic stones,  as  to  the  greater  bodies  of  the  solar 
fiystem,  that  we  feel  ourselves  proceeding  on 


surer  grounds.  Although  Halley  had  already 
pronounced  the  great  fire-ball  of  1686,  the  mo- 
tion of  which  was  in  opposition  to  that  of  the 
earth,  a  cosmic  phenomenon("),  Chladni  was 
the  first  (1794)  who,  in  the  most  general  terms, 
and  most  clearly  recognized  the  connection  be- 
twixt fire-balls  and  the  stones  that  fall  from  the 
atmosphere,  as  well  as  the  correspondence  be- 
tween the  motions  of  these  bodies  and  those 
of  the  planetary  masses  at  large(").  A  brill- 
iant confirmation  of  this  view  of  the  cosmic 
origin  of  such  phenomena  has  been  supplied  by 
Denison  Olmsted,  of  New-Haven,  Connecti- 
cut, in  his  observations  on  the  showers  of 
shooting  stars  and  fire-balls  which  made  their 
appearance  in  the  night  from  the  12th  to  the 
13th  of  November,  1833.  On  this  occasion,  all 
these  bodies  proceeded  from  the  same  quarter 
of  the  heavens — from  a  point,  namely,  near  the 
star  y  Leonis,  from  which  they  did  not  deviate, 
although  the  star,  in  the  course  of  the  length- 
ened observation,  changed  both  its  apparent 
elevation  and  its  azimuth.  Such  an  independ- 
ence of  the  rotation  of  the  earth  proclaimed 
that  the  luminous  bodies  came  from  without — 
from  outer  space  into  our  atmosphere.  Accord- 
ing to  Encke's  calculations  of  the  entire  series 
of  observations  that  were  made  in  the  United 
States  of  North  America,  between  the  paralells 
of  35°  and  42°,  the  whole  of  the  shooting  stars 
came  from  the  point  in  space  towards  which 
the  earth  was  moving  at  the  same  epoch(^*). 
In  the  subsequent  American  observations  on  the 
shooting  stars  of  November  1834  and  1837,  and 
the  Bremen  ones  of  1838,  the  general  parallel- 
ism of  their  courses,  and  the  direction  of  the 
meteors  from  the  constellation  Leo,  were  per- 
ceived. As  in  the  November  periodical  recur- 
rence of  shooting  stars,  a  more  decided  parallel 
and  particular  direction  has  been  noted  than  in 
the  case  of  those  that  appear  sporadically  at 
other  seasons,  so  in  the  August  phenomenon  it 
has  also  been  believed  that  the  bodies  came  for 
the  major  part  from  a  point  between  Perseus 
and  Taurus,  the  point  towards  which  the  earth 
is  tending  about  the  middle  of  the  month  of 
August.  This  was  particularly  remarked  in 
the  summer  of  1839.  This  peculiarity  in  the 
phenomenon  of  falling  stars,  the  direction  of 
retrograde  orbits  in  the  months  of  November 
and  August,  is  especially  worthy  of  being  either 
better  confirmed  or  refuted  by  the  most  careful 
observations  upon  future  occasions. 

The  altitudes  at  which  shooting  stars  make 
their  appearance,  by  which  must  be  understood 
the  periods  between  their  becoming  visible  and 
their  ceasing  to  be  so,  are  extremely  various ; 
in  a  general  way,  they  may  be  stated  as  vary- 
ing between  four  and  thirty-five  geographical 
miles.  This  important  result,  as  well  as  the 
extraordinary  velocity  of  the  problematical  as- 
teroids, was  first  arrived  at  by  Benzenberg  and 
Brandos,  by  means  of  a  series  of  contempora- 
neous observations  and  determinations  of  par- 
allax, at  either  extremity  of  a  base  hne  46,000 
feet  in  length(").  The  relative  velocity  of  the 
motion  was  from  four  and  a  quarter  to  nine 
miles  per  second ;  it  was  therefore  equal  to 
that  of  the  planets(38).  such  a  velocity  of 
movement,  as  well  as  the  frequently  observed 
course  of  shooting  stars  and  fire-balls  in  a  di- 
rection the  opposite  of  that  of  the  earth,  lias 


40 


SHOOTING?  STARS  AND  AEROLITES. 


been  used  as  a  principal  element  in  combating 
that  view  of  the  origin  of  aerolites,  in  which 
they  were  presumed  to  be  projected  from  still 
active  volcanoes  in  the  moon.  The  supposi- 
tion of  any  volcanic  power,  of  greater  or  less 
energy,  inherent  in  a  small  planetary  body  sur- 
rounded by  no  atmosphere,  is,  indeed,  in  the 
nature  of  things,  and  numerically  considered, 
extremely  arbitrary.  It  is  not  difficult,  indeed, 
to  conceive  the  reaction  of  the  interior  of  a 
planet  against  its  crust,  as  ten  or  even  a  hun- 
dred times  greater  than  that  which  we  now  ob- 
serve in  connection  with  the  volcanoes  of  the 
earth.  The  direction  of  the  masses,  too, 
which  could  be  projected  from  a  satellite  mo- 
ving from  west  to  east,  might  appear  retro- 
grade, in  consequence  of  the  earth,  in  its  orbit, 
arriving  later  at  the  point  of  its  path  where  the 
masses  fall.  But,  then,  if  the  entire  circle  of 
relations,  which  I  felt  myself  compelled  to  spe- 
cify, even  in  this  general  picture  of  nature,  to 
escape  the  suspicion  of  making  unfounded  as- 
sertions, be  surveyed,  it  will  be  found  that 
the  hypothesis  of  a  lunar  origin  of  meteoric 
stones(^')  is  dependent  on  a  majority  of  condi- 
tions, the  accidental  association  of  which  could 
alone  give  to  the  barely  possible,  the  form  and 
substance  of  reality.  The  admission  of  the 
original  existence  of  small  planetary  masses 
circulating  in  space,  is  simpler,  and  seems  more 
in  harmony  with  what  we  know  or  infer  with 
reference  to  the  formation  of  the  solar  system. 

It  is  highly  probable  that  a  great  proportion 
of  these  cosmic  bodies  pass  undestroyed  in  the 
vicinity  of  our  atmosphere,  and  only  suffer  a 
certain  deflection  in  the  excentricity  of  their 
orbits  by  the  attraction  of  the  earth.  We  may 
conceive  that  the  same  bodies  only  become  vis- 
ible to  us  again  after  the  lapse  of  several  years, 
and  when  they  have  made  many  revolutions 
round  their  orbit.  The  ascent  of  some  fire- 
balls and  shooting  stars  (which  Chladni  en- 
deavoured to  explain,  not  very  happily,  by  a 
reflection  produced  by  a  body  of  greatly  con- 
densed air)  appears,  at  first  sight,  to  be  a  con- 
sequence of  a  mysterious  projectile  force  throw- 
ing off  the  meteors  from  the  earth  ;  but  Bessel 
has  shown  on  theoretical  grounds,  and  indeed 
proved,  by  means  of  Feldt's  very  accurate  cal- 
culations, that  in  the  absence  of  perfect  agree- 
ment in  point  of  time,  of  the  disappearances  re- 
corded, there  is  not  one  amongst  the  whole  of 
the  observations  published  which  impresses  the 
assumption  of  an  ascent,  with  a  character  of 
probability,  none  which  does  not  allow  us  to  re- 
gard it  as  an  effect  of  observation(*°).  Wheth- 
er the  explosion  of  shooting  stars,  and  of  the 
smoking  and  flaming  fire-balls  which  do  not  al- 
ways move  in  straight  lines,  may  force  the  me- 
teors upwards  in  the  manner  of  rockets,  or  oth- 
er\yise  influence  the  direction  of  their  path,  in 
certain  cases,  as  Olbers  supposes,  must  remain 
matter  for  further  observation. 

Shooting  stars  fall  either  singly  and  rarely, 
and  at  all  seasons  indifferently,  or  in  crowds 
of  many  thousands  (Arabian  writers  compare 
them  to  swarms  of  locusts),  in  which  case  they 
are  periodical,  and  move  in  streams  generally 
parallel  in  direction.  Amongst  the  periodic 
showers,  the  most  remarkable  are  those  that 
occur  from  the  12th  to  the  14th  of  November, 
and  on  the  10th  of  August ;  the  "  fiery  tears" 


which  then  descend,  are  noticed  in  an  ancient 
English  church-calendar,  and  are  traditionally 
indicated  as  a  recurring  meteorological  inci- 
dent(*^).  Independently  of  this,  however,  pre- 
cisely in  the  night  from  the  12th  to  the  13th  of 
November,  1823,  according  to  Kloden,  there 
was  seen  at  Potsdam,  and  in  1832,  over  the 
whole  of  Europe  from  Portsmouth  to  Orenburg 
on  the  river  Ural,  and  even  in  the  southern 
hemisphere,  in  the  Isle  of  France,  a  great  mix- 
ture of  shooting  stars  and  fire-balls  of  the  most 
different  magnitudes  ;  but  it  appears  to  have 
been  more  especially  the  enormous  fall  of 
shooting  stars,  which  Olmsted  and  Palmer  ob- 
served in  North  America  between  the  12th  and 
13th  of  November,  1833,  when  they  appeared 
in  one  place  as  thick  as  flakes  of  snow,  and 
240,000  at  least  were  calculated  to  have  fallen 
in  the  course  of  nine  hours,  that  led  to  the  idea 
of  the  periodic  nature  of  the  phenomenon,  of 
great  flights  of  shooting  stars  being  connected 
with  particular  days.  Palmer  of  New  Haven 
recollected  the  fall  of  meteors  in  1799,  which 
Ellicot  and  I  first  described(*''),  and  from  which, 
by  the  juxtaposition  of  observations  which  I 
had  given,  it  was  discovered  that  the  phenom- 
enon had  occurred  simultaneously  over  the 
New  Continent  from  the  equator  to  New-Hern- 
hut  in  Greenland  (N.  Lat.  64°  14'),  betwixt  46° 
and  82°  of  Longitude.  The  identity  in  point 
of  time  was  perceived  with  amazement.  The 
stream,  which  was  seen  over  the  whole  vault 
of  heaven  between  the  12th  and  13th  of  No- 
vember, 1833,  from  Jamaica  to  Boston  (N.  L. 
40°  21'),  recurred  in  1834,  in  the  night  between 
the  13th  and  14th  of  November,  in  the  United 
States  of  North  America,  but  with  something 
less  of  intensity.  In  Europe,  its  periodicity 
since  this  epoch  has  been  confirmed  with  great 
regularity. 

A  second,  even  as  regularly  recurring  show- 
er of  shooting  stars  as  the  November  phenom- 
enon, is  the  one  of  the  month  of  August — the 
feast  of  St.  Lawrence  phenomenon — between 
the  9th  and  the  14th  of  the  month.  Muschen- 
broeck(")  had  already  called  attention  in  the 
middle  of  the  preceding  century  to.the  frequen- 
cy of  meteors  in  the  month  of  August ;  but 
their  periodic  and  certain  return  about  the  time 
of  the  feast  of  St.  Lawrence  was  first  pointed 
out  by  Quetelet,  Olbers,  and  Benzenberg.  In 
the  course  of  time  other  periodically  recurring 
showers  of  shooting  stars(**)  will  very  certain- 
ly h^  discovered — perhaps  from  the  22d  to  the 
25th  of  April ;  from  the  6th  to  the  12th  of  De- 
cember, and,  in  consequence  of  the  actual  fall 
of  aerolites  described  by  Capocci,  from  the  27th 
to  the  29th  of  November,  or  about  the  17th  of 
July. 

However  independent  all  the  phenomena  of 
falling  stars  yet  witnessed  may  have  been  of 
polar  elevation,  temperature  of  the  air,  and  oth- 
er climatic  relations,  there  is  still  one,  although 
perhaps  only  accidental,  accompanying  phenom- 
enon which  must  not  be  passed  by  unnoticed. 
The  Northern  Lights  showed  themselves  of 
great  intensity  during  the  most  brilliant  of  all 
these  natural  incidents,  that,  namely,  which 
Olmsted  has  described  (Nov.  12-13,  1833). 
The  same  thing  was  also  observed  in  Bremen 
in  1838,  where,  however,  the  periodic  fall  of 
meteors  was  less  remarkable  than  at  Rich- 


SHOOTING  STARS  AND  AEROLITES. 


a 


mond,  in  the  neighbourhood  of  London.  I  have 
also  referred,  in  another  work(**),  to  the  re- 
markable observation  of  Admiral  Wrangel, 
which  he  has  confirmed  to  me  verbally  oftener 
than  once,  that  during  the  appearance  of  the 
Northern  Lights,  on  the  Siberian  shores  of  the 
Icy  Sea,  certain  regions  of  the  heavens  which 
were  not  illuminated,  became  inflamed  and 
continued  to  glow  whilst  a  shooting  star  pass- 
ed through  them. 

The  difTerent  meteor-streams,  each  of  them 
made  up  of  myriads  of  little  planets,  probably 
intersect  the  orbit  of  our  earth  in  the  same 
way  as  Biela's  comet  doee.  Upon  this  view 
we  may  imagine  these  shoot-star  asteroids  as 
forming  a  closed  ring,  and  pursuing  their  course 
in  the  same  particular  orbit.  The  smaller  tel- 
escopic planets  between  Mars  and  Jupiter,  with 
the  exception  of  Pallas,  present  us,  in  their 
closely  connected  orbits,  with  a  similar  rela- 
tionship. It  is  impossible  as  yet  to  decide 
whether  alterations  in  the  epochs  at  which  the 
stream  becomes  visible  to  us,  whether  retarda- 
tions of  the  phenomenon,  to  which  I  long  ago 
directed  attention,  indicate  a  regular  recession 
or  change  of  the  nodes  (the  points  of  intersec- 
tion of  the  earth's  orbit  and  the  ring),  or  wheth- 
er from  unequal  clustering  or  very  dissimilar 
distances  of  the  little  bodies  from  each  other, 
the  zone  is  of  such  considerable  breadth,  that 
the  earth  only  passes  through  it  in  the  course 
of  several  days.  The  lunar  system  of  Saturn 
likewise  shows  us  a  group  of  most  intimately 
associated  planetary  bodies  of  amazing  breadth. 
In  this  group,  the  orbit  of  the  7th  or  outermost 
satellite,  is  of  so  considerable  a  diameter,  that 
the  earth,  in  her  orbit  round  the  sun,  would 
take  three  days  to  pass  over  a  space  of  like  ex- 
tent. Now,  if  we  suppose  that  the  asteroids 
are  unequally  distributed  in  the  course  of  one 
of  the  closed  rings  which  we  picture  to  our- 
selves as  forming  the  orbits  of  the  periodic  cur- 
rents, that  there  are  but  a  few  thickly  congre- 
gated groups  such  as  would  give  the  idea  of 
continuous  streams,  we  can  understand  where- 
fore such  brilliant  phenomena  as  those  of  No- 
vember 1799  and  1833  are  extremely  rare.  The 
acute  Gibers  was  inclined  to  announce  the  re- 
turn of  the  grand  spectacle,  in  which  shooting 
stars  mixed  with  fire-balls  should  fall  like  a 
shower  of  snow,  for  the  12th-14th  of  Novem- 
ber, 1867. 

Hitherto  the  current  of  the  November  aste- 
roids has  only  been  visible  over  limited  portions 
of  the  earth's  surface.  It  appeared,  for  exam- 
ple, with  great  splendour  in  England  in  the 
year  1837,  as  a  meteoric  shower ;  whilst  an 
experienced  and  very  attentive  observer  at 
Braunsberg,  in  Prussia,  saw  nothing  more  than 
a  few  scattered  shooting  stars  in  the  course  of 
the  same  night,  from  seven  o'clock  in  the 
evening  till  sun-rise,  the  sky  having  continued 
uninterruptedly  clear  the  whole  of  the  time. 
Bessel  concluded  from  this,  "  that  a  group  of 
the  great  ring  which  is  occupied  by  these  bod- 
ies, of  but  limited  extent,  had  approached  the 
earth  over  England,  whilst  districts  to  the  east 
passed  through  a  relatively  empty  portion  of 
the  ring"(*^).  Should  the  idea  of  a  regular  pre- 
cession or  variation  of  the  nodal  lines,  occa- 
sioned by  perturbations,  acquire  greater  likeli- 
hood, the  discovery  of  older  observations  of  the 
F 


phenomenon  would  become  a  matter  of  partic- 
ular interest.  The  Chinese  annals,  in  which, 
beside  the  appearance  of  comets,  there  are  also 
notices  of  gi»at  showers  of  shooting  stars,  go 
back  beyond  the  time  of  Tyrtaeus,  or  the  second 
Messenic  war.  They  describe  two  streams  oc- 
curring in  the  month  of  March,  one  of  which 
is  687  years  older  than  the  commencement  of 
the  Christian  era.  Edward  Biot  has  already 
remarked,  that  among  the  fifty-two  appearan- 
ces which  he  finds  recorded  in  the  Chinese  an- 
nals, the  most  frequently  recurring  were  those 
that  fell  near  the  date  from  the  20th  to  the  22d 
of  July  (old  style),  which  may  very  possibly  be 
the  now  advanced  stream  occurring  about  the 
time  of  the  feast  of  St.  Lawrence(*^).  If  the 
great  fall  of  shooting  stars  which  Bogulawski, 
jun.,  finds  recorded  in  Benessius  de  Horowic's 
"  Chronicon  Ecclesiae  Pragensis,"  as  having 
been  seen  in  full  day  light  on  the  21st  of  Octo- 
ber, 1366  (old  style),  corresponds  with  our  pres- 
ent November  fall,  the  precession  in  the  course 
of  447  years  informs  us  that  this  shoot-star 
system  (that  is  to  say,  its  common  point  of 
gravity),  describes  a  retrograde  course  about 
the  sun.  It  also  follows,  from  the  views  now 
developed,  that  when  seasons  pass  by  in  which 
neither  of  the  streams  as  yet  observed — that, 
namely,  of  November  and  that  of  August — is 
seen  in  any  part  of  the  earth,  the  reason  of 
this  lies  either  in  the  interruption  of  the  ring — 
in  other  words,  in  the  occurrence  of  gaps  or 
vacancies  between  the  clusters  of  asteroids 
that  follow  each  other  —  or,  as  Poisson  will 
have  it,  in  the  influence  which  the  larger  plan- 
ets exercise  upon  the  form  and  position  of  the 
ring(*^). 

The  solid,  heated,  although  not  red-hot,  mass- 
es which  are  seen  to  fall  to  the  earth  from  fire- 
balls by  night,  from  .small  dark  clouds  by  day, 
accompanied  with  loud  noises,  the  sky  being 
generally  clear  at  the  time,  show,  on  the  whole, 
a  very  obvious  similarity,  in  point  of  external 
form,  in  the  character  of  their  crust  and  the 
chemical  composition  of  their  principal  ingre- 
dients. This  they  have  maintained  through 
centuries,  and  in  every  region  of  the  earth  in 
which  they  have  been  collected.  But  so  re- 
markable and  early  asserted  a  physiognomical 
equality  in  these  dense  meteoric  masses  is 
subject  to  many  individual  exceptions  How 
different  are  the  readily  forged  masses  of  iron 
of  Hradschina,  in  the  district  of  Agram,  or  that 
of  the  banks  of  the  Sisim,  in  the  government 
of  Jenesiesk,  which  have  become  celebrated 
through  Pallas,  or  those  which  I  brought  with 
me  from  Mexico(*'),  all  of  which  contain  96  per 
cent,  of  iron,  from  the  aerolites  of  Siena,  which 
scarcely  contain  2  per  cent,  of  this  metal,  from 
the  earthy  meteoric  stone  of  Alais  (Dep.  du 
Gard),  which  crumbles  when  put  into  water, 
and  from  those  of  Jonzac  and  Juvenas,  which, 
without  metallic  iron,  contain  a  mixture  of 
oryctognostically  distinguishable,  crystalline 
and  distinct  constituents  !  These  diversities 
have  led  to  the  division  of  the  cosmical  masses 
into  two  classes — nickeliferous  meteoric  iron, 
and  fine  or  coarse  grained  meteoric  stones. 
Highly  characteristic  is  the  crust,  though  it  be 
but  a  few  tenths  of  a  line  in  thickness,  often 
shining  like  pitch,  and  occasionally  vemed("). 
So  far  as  I  know,  it  has  only  been  found  want- 


43 


SHOOTING  STARS  AND  AEROLITES. 


ing  in  the  meteoric  stone  of  Chantonnay,  in 
La  Vendee,  which,  on  the  other  hand — and 
this  is  equally  rare — exhibits  pores  and  vesicu- 
lar cavities  like  the  meteoric  ston^  of  Juvenas. 
In  every  instance  the  black  crust  is  as  sharply 
separated  from  the  clear  gray  mass,  as  is  the 
dark-coloured  crust  or  varnish  of  the  white 
granite  blocks  which  I  brought  from  the  cata- 
racts of  the  Orinoko("),  and  which  are  also  met 
with  by  the  side  of  other  cataracts  in  different 
quarters  of  the  globe — those  of  the  Nile,  the 
Congo,  &c.  It  is  impossible  to  produce  any- 
thing in  the  strongest  heat  of  the  porcelain 
furnace  which  shall  be  so  distinct  from  the  un- 
altered matter  beneath,  as  is  the  crust  of  aero- 
lites from  their  general  mass.  Some,  indeed, 
will  have  it  that  here  and  there  indications  of 
penetration  of  fragments,  as  if  by  kneading, 
appear ;  but  in  general  the  condition  of  the 
mass,  the  absence  of  flattening  from  the  fall, 
and  the  not  very  remarkable  heat  of  the  mete- 
oric stone,  when  touched  immediately  after  its 
fall,  indicate  nothing  like  a  state  of  fusion  of 
the  interior  during  the  rapid  passage  from  the 
limits  of  the  atmosphere  to  the  earth. 

The  chemical  elements  of  which  meteoric 
masses  consist,  upon  which  Berzelius  has 
thrown  so  much  light,  are  the  same  as  those 
which  we  encounter  scattered  through  the 
crust  of  the  earth.  They  consist  of  eight  met- 
als (iron,  nickel,  cobalt,  manganese,  chrome, 
copper,  arsenic,  and  tin) ;  five  earths ;  potash 
and  soda  ;  sulphur,  phosporus,  and  carbon  ;  in 
all,  one-third  of  the  entire  number  of  simple 
substances  at  present  known.  Despite  this 
similarity  to  the  ultimate  elements  into  which 
inorganic  bodies  are  chemically  decomposable, 
the  appearance  of  meteoric  masses  has  still 
something  that  is  generally  strange  to  us  ;  the 
kind  of  combination  of  the  elements  is  unlike 
all  that  our  terrestrial  mountain  and  rocky 
masses  exhibit.  The  native  iron,  which  is  met 
with  in  almost  the  whole  of  them,  gives  them 
a  peculiar,  but  not  therefore  a  lunar  character ; 
for,  in  other  regions  of  space,  in  other  plane- 
tary bodies  besides  the  moon,  water  may  be 
entirely  wanting,  and  processes  of  oxidation 
may  be  rare. 

The  cosmic  gelatinous  vesicles,  the  nostoc- 
like  organic  masses,  which  have  been  attribu- 
ted to  shooting  stars  ever  since  the  middle 
ages,  and  the  pyrites  of  Sterlitamak  (westward 
from  the  Ural  Mountains),  which  have  been 
said  to  be  composed  of  hail-stones  in  the  inte- 
rior, belong  to  the  fables  of  meteorology(*2). 
It  is  only  the  finely  granular  texture,  only  the 
mixture  of  olivine,  augite,  and  labrador  spar("), 
of  some  aerolites,  of  the  doloritic-looking  mass 
of  Juvenas  in  Ardeche,  for  example,  that  gives 
them  somewhat  more  of  an  indigenous  charac- 
ter, as  G.  Rose  has  shown.  These  aerolites, 
indeed,  contain  crystalline  substances  exactly 
similar  to  those  of  the  crust  of  our  Earth  ;  and 
in  Pallas's  Siberian  mass  of  meteoric  iron,  the 
olivine  is  only  distinguished  by  the  absence 
of  nickel,  which  is  there  replaced  by  oxide  of 
tin(**).  As  meteoric  olivine,  like  that  of  our 
basalt,  contains  from  47  to  49  per  cent,  of  mag- 
nesia, and  this  earth,  according  to  Berzelius, 
generally  constitutes  one-half  of  the  earthy  in- 
gredients of  aerolites,  we  must  not  be  astoi- 
ished  at  the  large  quantity  of  silicate  of  mag- 


nesia which  we  find  in  these  cosmic  masses. 
If  the  aerolite  of  Juvenas  contains  separable 
crystals  of  augite  and  labrador,  it  is  at  least 
probable,  from  the  numerical  relations  of  the 
ingredients,  that  the  meteoric  mass  of  Cha- 
teau-Renard  is  a  diorite  composed  of  horn- 
blende and  albite,  and  those  of  Blansko  and 
Chantonnay  of  hornblende  and  labrador.  The 
indications  of  a  telluric  or  atmospheric  origin 
of  aerolites,  which  have  been  derived  from  the 
oryctognostic  resemblances  just  mentioned,  do 
not  appear  to  me  of  any  great  weight.  Where- 
fore should  not — and  here  I  might  refer  to  a 
remarkable  conversation  between  Newton  and 
Conduit  at  Kensington(**) — wherefore  should 
not  the  matter  belonging  to  a  particular  cluster 
of  celestial  bodies,  to  the  same  planetary  sys- 
tem, be  for  the  major  part  the  same  1  Why 
should  it  not  be  so,  when  we  feel  at  liberty  to 
surmise  that  these  planets,  like  all  larger  and 
smaller  conglobated  masses  which  revolve 
about  the  sun,  have  separated  from  particular 
and  formerly  much  more  widely-expanded  sun- 
atmospheres,  as  from  vaporous  rings,  and 
which  originally  held  their  courses  round  the 
central  bodyl  We  are  not,  I  believe,  more 
authorized  to  regard  nickel  and  iron,  olivine 
and  pyroxene  (augite),  which  we  find  in  me- 
teoric stones,  as  exclusively  terrestrial,  than  I 
should  have  been  had  I  indicated  the  German 
plants  which  I  found  beyond  the  Obi,  as  Euro- 
pean species  of  the  flora  of  northern  Asia.  If 
the  elementary  matters  in  a  group  of  planetary 
bodies  of  various  magnitudes  be  identical,  why 
should  they  not  also,  in  harmony  with  their 
several  affinities,  run  into  determinate  combi- 
nations— in  the  polar  circle  of  Mars,  into  white 
and  brilliant  snow  and  ice ;  in  other  smaller 
cosmic  masses  into  mineral  species  that  con- 
tain crystalline,  augite,  olivine,  and  labrador  1 
Even  in  the  region  of  the  merely  Conjectu- 
ral, the  unbridled  caprice  that  despises  all  in- 
duction must  not  be  suffered  to  control  opin- 
ion. 

The  extraordinary  obscurations  of  the  sun 
which  have  occasionally  taken  place,  during 
which  the  stars  became  visible  at  mid-day  (as 
in  the  three  days'  darkness  of  the  year  1547, 
about  the  time  of  the  fateful  battle  near  Miihl- 
berg),  and  which  are  not  explicable  on  the  sup- 
position of  a  cloud  of  volcanic  ashes,  or  of  a 
dense  dry-fog,  were  ascribed  by  Kepler,  at  one 
time,  to  a  materia  cometica,  at  another  to  a 
black  cloud,  the  product  of  sooty  exhalations 
from  the  sun's  body.  The  observations  of 
shorter  periods  of  darkness — of  three  and  six 
hours,  in  the  years  1090  and  1203— Chladni 
and  Schnurrer  have  explained  by  the  passage 
of  meteoric  masses.  And  since  the  stream  of 
shooting  stars  from  the  direction  of  its  orbit 
has  been  regarded  as  forming  a  closed  ilwg, 
the  epochs  of  these  mysterious  celestial  phe- 
nomena have  been  brought  into  a  remarkable 
connection  with  the  regularly  recurring  show- 
ers of  shooting  stars.  Adolph  Erman  has, 
with  great  acuteness,  and  after  a  careful  analy- 
sis of  all  the  data  collected  up  to  the  present 
time,  directed  the  attention  of  philosophers  to 
the  coincidence  of  the  conjunction  with  the 
sun,  as  well  of  the  August  asteroids  (7th  of 
February)  as  of  the  November  asteroids  (12th 
of  May),  at  the  epoch  which  coincides  with 


SHOOTING  STARS  AND  AEROLITES. 


43 


the  popular  belief  in  the  celebrated  cold  days  of 
Mamertius,  Pancratius,  and  Servatias(*®). 

The  Greek  natural  philosophers,  little  dis- 
posed in  general  to  observation,  but  incessant- 
ly, inexhaustibly  addicted  to  speculation  on  the 
manifold  import  of  half-seen  truths,  have  left 
views  behind  them  on  shooting  stars  and  me- 
teoric stones,  several  of  which  chime  in  most 
remarkably  with  those  at  present  so  commonly 
entertained  of  the  cosmic  nature  of  the  phe- 
nomenon. ♦'  Shooting  stars."  says  Plutarch(*^), 
in  the  Life  of  Lysander,  "  according  to  the  opin- 
ion of  some  naturalists,  are  not  excretions  and 
emanations  of  the  ethereal  fire,  quenched  in 
the  air  immediately  after  their  ignition ;  nei- 
ther are  they  any  kindling  and  combustion  of 
the  air,  produced  by  those  which  have  become 
dissolved  in  quantities  in  the  upper  regions  ; 
they  are  rather  a  fall  of  celestial  bodies,  occa- 
sioned by  a  certain  abatement  of  the  centrifu- 
gal force,  and  the  impulse  of  an  irregular  mo- 
tion, and  are  cast  down,  not  only  upon  the  in- 
habited earth,  but  also  beyond  it  into  the  ocean, 
on  which  account  they  are  not  then  found." 
Diogenes  of  Apollonia(*^)  speaks  still  more 
clearly  on  the  subject.  According  to  his  view, 
"  along  with  the  visible  stars,  others  move 
that  are  invisible,  and  therefore  are  unnamed. 
These  last  frequently  fall  to  the  earth  and  are 
extinguished,  as  was  the  case  with  the  stony 
star  which  descended  in  fire  at  Aegos  Pota- 
mos."  The  Apollonian,  who  also  regards  all 
the  other  stars  (the  luminous  ones)  as  pumice- 
like bodies,  probably  founded  his  opinions  of 
the  nature  of  shooting  stars  and  meteoric 
masses  upon  the  doctrines  of  Anaxagoras,  of 
Clazomenae,  who  maintained  that  all  the  heav- 
enly bodies  were  '•  mineral  masses,  which  the 
fiery  ether,  in  the  power  of  its  revolution,  had 
torn  from  the  earth,  had  ignited  and  converted 
into  stars."  In  the  Ionic  school,  according  to 
the  statement  of  Diogenes  of  Apollonia,  and  as 
it  has  come  down  to  us,  aerolites  and  the  heav- 
enly bodies  were  placed  in  one  and  the  same 
class  ;  both  are  alike  terrestrial  in  their  ori- 
ginal production ;  but  only  in  the  sense  that 
the  earth,  as  the  central  body,  had  formerly(") 
fashioned  all  around  her ;  in  the  same  way  as 
our  present  ideas  lead  us  to  conceive  that  the 
planets  of  a  system  arise  from  the  extended 
atmosphere  of  another  central  body — namely, 
the  sun.  These  views,  consequently,  are  not 
to  be  confounded  with  that  which  speaks  fa- 
miliarly of  meteoric  stones,  as  of  telluric  or  at- 
mospheric origin,  nor  yet  with  the  extraordi- 
nary conjecture  of  Aristotle,  to  the  effect  that 
the  enormous  mass  of  Aegos  Potamos  had 
been  raised  by  a  tempestuous  wind. 

The  presumptuous  skepticism  which  rejects 
facts  without  caring  to  examine  them,  is,  in 
many  respects,  even  more  destructive  than  un- 
critical credulity.  Both  interfere  with  rigour 
of  mvestigation.  Although,  for  fifteen  hundred 
years,  the  annals  of  various  nations  have  told 
of  the  fall  of  stones  from  the  sky— although  sev- 
eral instances  of  the  circumstance  are  placed 
beyond  all  question  by  the  unimpeachable  tes- 
timony of  eye-witnesses— ^although  the  Baetylia 
formed  an  important  part  of  the  meteor-wor- 
ship of  the  ancients,  and  the  companions  of 
Cortes  saw  the  aerolites  in  Cholula,  which  had 
fallen  upoji  the  neighbouring  pyramid— although 


Caliphs  and  Mongolian  princes  have  had  sword 
blades  forged  from  meteoric  masses  that  had 
but  lately  fallen,  and  men  have  even  been  kill- 
ed by  stones  from  heaven  (a  certain  monk  at 
Crema,  on  the  4th  September,  1511;  another 
monk  in  Milan,  1650  ;  and  two  Sweedish  sailors 
on  ship-board,  1674),  so  remarkable  a  cosmical 
phenomenon  remained  almost  unnoticed,  and, 
in  its  intimate  relationship  with  the  rest  of  the 
planetary  system,  unappreciated,  until  Chladni, 
who  had  already  gained  immortal  honour  in 
physics  by  his  discovery  of  phonic  figures,  di- 
rected attention  to  the  subject.  But  he  who  is 
penetrated  with  the  belief  of  this  connection,  if 
he  be  susceptible  of  emotions  of  awe  through 
natural  impressions,  will  be  filled  with  solemn 
thoughts  in  presence,  not  of  the  brilliant  specta- 
cles of  the  November  and  August  phenomena 
only,  but  even  on  the  appearance  of  a  solitary 
shooting  star.  Here  is  a  sudden  exhibition  of 
movement  in  the  midst  of  the  realm  of  noctur- 
nal peace.  Life  and  motion  occur  at  intervals 
in  the  quiet  lustre  of  the  firmament.  The  track 
of  the  falling  star,  gleaming  with  a  palely  lus- 
tre, gives  us  a  sensible  representation  of  a  path 
long  miles  in  length  across  the  vault  of  heaven  ; 
the  burning  asteroid  reminds  us  of  the  exist- 
ence of  universal  space  every  where  filled  with 
matter.  When  we  compare  the  volume  of  the 
innermost  satellite  of  Saturn,  or  that  of  Ceres, 
with  the  enormous  volume  of  the  Sun,  all  rela- 
tion of  great  and  small  vanishes  from  the  im- 
agination. The  extinction  of  the  stars  that 
have  suddenly  blazed  up  in  several  parts  of  the 
heavens,  in  Cassiopea,  in  Cygnus,  and  in  Ophi- 
ucus,  leads  us  to  admit  the  existence  of  dark 
or  non-luminous  celestial  bodies.  Conglobed 
into  minor  masses,  the  shooting-star  asteroids 
circulate  about  the  sun,  intersect  the  paths  of 
the  great  luminous  planets,  after  the  manner  of 
comets,  and  become  ignited  when  they  approach 
or  actually  enter  the  outermost  strata  of  our 
atmosphere. 

With  all  other  planetary  bodies,  with  the 
whole  of  nature  beyond  the  limits  of  our  at- 
mosphere, we  are  only  brought  into  relation- 
ship by  means  of  light,  of  radiant  heat,  which 
is  scarcely  to  be  separated  from  light("),  and 
the  mysterious  force  of  attraction  which  dis- 
tant masses  exert  upon  our  earth,  our  ocean, 
and  our  atmosphere,  according  to  the  quantity 
of  their  material  parts.  We  recognize  a  totally 
different  kind  of  cosmic,  and  most  peculiarly 
material  relationship,  in  the  fall  of  shooting- 
stars  and  meteoric  stones,  when  we  regard 
them  as  planetary  asteroids.  These  are  no 
longer  bodies,  which,  through  the  mere  excite- 
ment of  pulses,  influence  us  from  a  distance  by 
their  light  or  their  heat,  or  which  move  and  are 
moved  by  attraction  ;  they  are  material  bodies, 
which  have  come  from  the  realms  of  space  into 
our  atmosphere,  and  remain  with  our  earth. 
Through  the  fall  of  a  meteoric  stone,  we  ex- 
perience the  only  possible  contact  of  aught  that 
does  not  belong  to  our  planet.  Accustomed  to 
know  all  that  is  non-telluric  solely  through 
measurement,  through  calculation,  through  in- 
tellectual induction,  we  are  amazed  when  we 
touch,  weigh,  and  subject  to  analysis  a  mass 
that  has  belonged  to  the  world  beyond  us.  Thus 
does  the  reflecting,  spiritualized  excitement  of 
the  feeUngs  work  upon  imagination,  in  circum- 


44 


THE  ZODIACAL  LIGHT. 


stances  where  vulgar  sense  sees  nothing  but  dy- 
ing sparks  in  the  clear  vault  of  heaven,  and  in  the 
black  stone  that  falls  from  the  crackling  cloud 
the  crude  product  ofsome  vt^ild  force  of  nature. 
If  the  crowd  of  shooting  asteroids,  upon 
which  we  have  paused  so  long  with  pleasure, 
be  assimilated  in  some  respects,  in  their  small 
masses  and  in  the  variety  of  their  orbits,  with 
comets,  they  are  still  essentially  distinguish- 
ed from  these  bodies  in  this — that  we  first  be- 
come aware  of  their  existence  almost  in  the 
moment  of  their  destruction,  when  fettered  by 
the  earth  they  become  luminous,  and  ignite. 
But  to  embrace  everytJiing  that  belongs  to  our 
solar  system,  which  has  now  become  so  com- 
plex, so  rich  in  variety  of  forms,  by  the  discov- 
ery of  the  telescopic  planets,  of  the  inner  com- 
ets of  short  period,  and  the  meteoric  asteroids, 
we  have  still  to  speak  particularly  of  the  ring 
of  Zodiacal  Light,  to  which  we  have  already 
alluded  incidentally  oftener  than  once.  He  who 
has  lived  for  years  in  the  zone  of  the  palms, 
retains  a  delightful  recollection  of  the  mild  ra- 
diance with  which  the  zodiacal  light,  rising  like 
a  pyramid  from  the  horizon,  illumines  a  portion 
of  the  unvarying  length  of  the  tropical  night. 
I  have  seen  it  occasionally  more  intensely  lu- 
minous than  the  milky  way  in  Saggitarius  ;  and 
that  not  only  in  the  thin  and  dry  atmosphere  of 
the  summits  of  the  Andes,  at  the  height  of 
twelve  or  fourteen  thousand  feet  above  the  lev- 
el of  the  sea,  but  also  in  the  boundless  grassy 
plains  (Llanos)  of  Venezuel-a,  as  well  as  on  the 
coasts  of  the  ocean  under  the  ever-serene  sky 
of  Cumana.  Of  most  peculiar  beauty  was  the 
phenomenon,  when  small  fleecy  clouds  appear- 
ed projected  upon  the  light,  and  stood  out  pic- 
turesquely from  the  luminous  back-ground.  A 
leaf  of  my  journal,  during  the  sea  voyage  from 
Lima  to  the  western  coast  of  Mexico,  preserves 
the  memorial  of  this  air-picture  :  "  For  the  last 
three  or  four  nights  (between  10°  and  14°  N. 
lat.)  I  see  the  zodiacal  light  with  a  splendour 
such  as  I  have  never  observed  before.  In  this 
part  of  the  Pacific,  judging  from  the  brilliancy 
of  the  stars,  and  the  distinctness  of  the  nebulae, 
the  transparency  of  the  air  is  wonderfully  great. 
From  the  14th  to  the  19th  of  March,  very  reg- 
ularly for  three-quarters  of  an  hour  after  the 
disc  of  the  sun  has  dipped  into  the  sea,  there  is 
no  trace  of  the  zodiacal  light,  although  it  is  by 
this  time  completely  dark  ;  but,  an  hour  after 
sun-set,  it  suddenly  becomes  visible,  of  great 
brilliancy,  between  Aldebaran  and  the  Pleiades ; 
and  on  the  18th  of  March  having  an  altitude  of 
39°  5'.  Long  narrow  stripes  of  cloud  show 
themselves,  scattered  over  the  beautiful  blue, 
and  deep  on  the  horizon  in  front  of  a  kind  of 
yellow  screen.  The  higher  clouds  are  play- 
ing from  time  to  time  with  variegated  tints.  It 
seems  as  if  the  sun  were  setting  for  the  second 
time.  On  this  side  of  the  vault  of  heaven,  the 
brilliancy  of  the  night  appears  to  be  increased, 
almost  as  it  is  in  the  first  quarter  of  the  moon. 
Towards  ten  o'clock,  the  zodiacal  light,  in  this 
part  of  the  Pacific,  was  usually  extremely  faint ; 
about  midnight  I  could  merely  perceive  a  trace 
of  it.  On  the  16th  of  March,  when  the  phe- 
nomenon presented  itself  in  its  greatest  splen- 
dour, there  was  a  counter-blush  of  mild  light 
apparent  in  the  east."  In  our  misty  northern 
temperate  zone,  as  it  is  called,  the  zodiacal 


light  is  only  to  be  distinctly  seen  in  the  early 
spring,  after  the  evening  twilight,  in  the  west- 
ern, and  towards  the  end  of  autumn  before  the 
morning  twilight,  in  the  eastern  horizon. 

It  is  difficult  to  comprehend  how  a  natural 
phenomenon,  so  remarkable  as  the  zodiacal 
light,  should  only  first  have  attracted  the  atten- 
tion of  natural  philosophers  and  astronomers 
about  the  middle  of  the  17th  century,  and  how 
it  could  have  escaped  the  observant  Arabians 
in  Ancient  Bactria,  on  the  Euphrates,  and  in 
the  south  of  Spain.  The  tardy  observation  of 
the  nebulae  in  Andromeda  and  Orion,  first  de- 
scribed by  Simon  Marius  and  Huygens,  excites 
almost  equal  astonishment.  The  first  distinct 
description  of  the  zodiacal  light  is  contained  in 
Childrey's  Britannia  Baconica("),  of  the  year 
1661  ;  the  first  observation  upon  it  may  have 
been  made  two  or  three  years  earlier  ;  but 
Dominic  Cassini  has  the  indisputable  merit  of 
having,  in  the  spring  of  1683,  investigated  the 
phenomenon  in  all  its  relations  in  space.  The 
luminous  appearance  which  he  observed  in 
1668,  at  Bologna,  and  which  was  seen  at  the 
same  time  in  Persia  by  the  celebrated  travel- 
ler, Chardin,  (the  court- astrologers  of  Ispahan 
called  this  light,  which  they  had  never  seen 
before,  nyzek,  or  little  lance,)  was  not,  as  has 
been  frequently  said("),  the  zodiacal  light,  but 
the  monstrous  tail  of  a  comet,  whose  head  was 
hidden  amidst  the  vapours  of  the  horizon,  and 
which,  in  point  of  length  and  appearance,  pre- 
sented many  points  of  resemblance  to  the  great 
comet  of  1843.  It  might  be  maintained,  with 
no  slight  show  of  probability,  that  the  remark- 
able light,  rising  pyramidally  from  the  earth, 
which  was  seen  in  the  eastern  sky  for  forty 
nights  in  succession,  on  the  lofty  plateau  of 
Mexico  in  1509,  was  the  zodiacal  light.  I  find 
this  phenomenon  mentioned  in  an  ancient  Az- 
tekan  manuscript  (Codex  Telleriano-Remensis) 
of  the  Royal  Library  at  Paris(^3). 

The  Zodiacal  Light,  of  primeval  antiquity, 
doubtless,  though  first  discovered  in  Europe  by 
Childery  and  Cassini,  is  not  the  luminous  at- 
mosphere of  the  sun  itself;  for  this,  from  me- 
chanical laws,  cannot  be  more  oblate  than  in 
the  ratio  of  two  to  three,  and  not  more  dilated 
than  9-20ths  of  Mercury's  distance.  The  same 
laws  determine  that,  in  the  case  of  a  revolving 
planetary  body,  the  height  or  distance  of  the 
extreme  limits  of  its*  atmosphere — the  point, 
namely,  where  gravity  and  the  centrifugal  force 
are  in  equilibrium — is  that  alone  in  which  a 
satellite  can  revolve  around  this  in  the  same 
time  as  the  primary  rotates  upon  its  axis("). 
Such  a  limitation  of  the  sun's  atmosphere  in  its 
present  concentrated  state,  comes  to  be  more 
particularly  remarkable  when  we  compare  the 
central  body  of  our  system  with  the  nucleus  of 
other  nebulous  stars.  Herschel  discovered 
many  in  which  the  semidiameter  of  the  burr 
which  surrounds  the  star  appears  under  an  an- 
gle of  150".  Assuming  a  parallax  which  does 
not  quite  reach  1",  we  find  the  outermost  neb- 
ulous layer  of  such  a  star  150  times  farther 
from  its  centre  than  the  earth  is  distant  from 
the  sun.  Were  the  nebulous  star  in  the  place 
of  our  sun,  consequently,  its  atmosphere  would 
not  merely  include  the  orbit  of  Uranus,  but 
would  extend  8  times  beyond  it("). 

With  the  narrow  limits  of  the  sun's  atmo- 


TRANSLATION  OF  THE  SUN  IN  SPACE. 


45 


sphere  now  indicated,  there  is  great  probability 
in  the  hypothesis  which  assumes  the  existence 
of  an  extremely  oblate  ring  of  nebulous  or  va- 
porous matter  revolving  freely  in  space  be- 
tween the  orbits  of  Venus  and  Mars,  as  the  ma- 
terial cause  of  the  zodiacal  light(").  Mean- 
time, of  its  proper  material  dimensions,  of  its 
increment  by  emanations  from  the  tails  of  myr- 
iads of  comets  which  approach  near  to  the 
sunC^),  of  the  singular  variability  of  its  extent 
— for  it  seems  at  times  not  to  extend  beyond  the 
orbit  of  the  earth,  and  lastly,  of  its  very  prob- 
able close  connection  with  the  denser  world- 
ether  in  the  vicinity  of  the  sun— nothing  cer- 
tain can  be  concluded.  The  vaporiform  par- 
ticles of  which  the  ring  consists,  and  which 
circulate  about  the  sun  in  conformity  with  plan- 
etary laws,  may  either  be  self-luminous,  or 
lighted  by  the  sun.  Even  a  terrestrial  haze  or 
fog  (and  the  fact  is  very  remarkable)  appeared 
at  the  time  of  the  new  moon  (1743),  which  at 
midnight  was  so  phosphorescent  that  objects 
at  the  distance  of  600  feet  could  be  plainly  dis- 
tinguished by  its  light^^).  In  the  tropical  cli- 
mate of  South  America,  the  variable  strength 
of  light  of  the  zodiacal  gleam  struck  me  at 
times  with  amazement.  As  I  there  passed  the 
beautiful  nights  in  the  open  air,  on  the  banks 
of  rivers  and  in  the  grassy  plains  (Llanos)  for 
several  months  together,  I  had  opportunities  of 
observing  the  phenomenon  with  care.  When 
the  zodiacal  light  was  at  its  very  brightest,  it 
sometimes  happened  that  but  a  few  minutes 
afterwards  it  became  notably  weakened,  and 
then  it  suddenly  gleamed  up  again  with  its 
former  brilliancy.  In  particular  instances,  I 
believed  that  I  remarked — not  any  thing  of  a 
ruddy  tinge,  or  an  inferior  arched  obscuration, 
or  an  emission  of  sparks,  such  as  Mairan  de- 
scribes, but  a  kind  of  unsteadiness  and  flicker- 
ing of  the  light.  Is  it  that  there  are  ^ny  pro- 
cesses going  on  in  the  vaporous  ring  itself  1  or 
is  it  not  more  likely  that,  though  I  could  detect 
no  change,  by  the  meteorolojgical  instruments, 
in  the  temperature  and  moistness  of  the  re- 
gions of  the  atmosphere  immediately  above  the 
ground,  and  though  small  stars  of  the  fifth  and 
sixth  magnitudes  appeared  to  shine  with  undi- 
minished strength  of  light,  that  in  the  superior 
strata  of  the  atmosphere  condensations  were 
proceeding  which  modified  the  transparency,  or 
rather  the  reflection  of  the  light,  in  a  peculiar 
and,  to  us,  unknown  manner  1  For  the  as- 
sumption of  such  meteorological  processes  on 
the  limits  of  our  atmosphere,  the  "explosions 
and  pulsations"  observed  by  the  acute  01- 
bers(^^),  "  which,  in  the  course  of  a  few  sec- 
onds, went  trembling  through  the  whole  of  a 
comet's  tail,  with  the  effect  now  of  lengthening, 
now  of  abridging  it  by  several  degrees,"  appear 
to  vouch.  "  As  the  several  parts  of  the  mill- 
ions-of-miles-long  tail  are  at  very  different  dis- 
tances from  the  earth,  the  laws  of  the  velocity 
and  propagation  of  light  do  not  permit  us  to 
suppose  that  actual  alterations  in  a  body  filling 
an  extent  of  space  so  vast,  could  be  perceived 
by  us  in  such  short  intervals  of  time."  These 
considerations  by  no  means  exclude  the  reality 
of  varying  emanations  around  the  condensed 
nuclear  envelopes  of  a  comet,  the  reality  of 
suddenly  supervening  brightenings  of  the  zodi- 
acal light,  through  internal  molecular  move- 


ments, through  alternately  augmented  or  di- 
minished reflections  of  light  by  the  matter  of 
the  luminous  ring;  they  should  only  make  us 
careful  to  distinguish  between  them  and  all  that 
belongs  to  the  celestial  ether — to  universal 
space  itself,  or  to  the  aerial  strata  composing 
the  atmosphere  through  which  we  see.  What 
in  other  respects  takes  place  in  the  outer  limits 
of  our  atmosphere — the  subject  of  great  diver- 
sity of  opinion — is,  as  well-observed  facts  in- 
dicate, by  no  means  to  be  completely  or  satis- 
factorily explained.  The  wonderful  lightness 
of  many  whole  nights  of  the  year  1831,  in  which 
small  print  could  be  read  at  midnight  in  Italy 
and  the  north  of  Germany,  is  in  obvious  con- 
tradiction with  all  that  the  latest  and  ablest  ob- 
servations on  the  crepuscular  theory,  and  the 
height  of  our  atmosphere,  make  known("). 
Luminous  phenomena  are  dependent  on  con- 
ditions that  are  yet  unexplored,  the  unstable- 
ness  of  which,  within  the  limits  of  the  twilight, 
as  well  as  in  connection  with  the  zodiacal 
light,  strike  us  with  astonishment. 

Thus  far  we  have  considered  what  belongs 
to  our  sun,  and  the  world  of  formations  that  is 
ruled  by  him — the  primary  and  secondary  plan- 
ets, comets  of  shorter  and  longer  periods  of 
revolution,  meteoric  asteroids  which  move  sin- 
gly in  closed  rings,  or  in  multitudes  like  a 
stream ;  finally,  a  luminous  nebulous  ring  which 
circles  round  the  sun  near  to  the  orbit  of  the 
earth,  and  which  from  its  position  may  remain 
with  its  name  of  zodiacal  light.  Every  where 
the  Law  of  Return  prevails  in  the  motions, 
how  different  soever  the  measure  of  the  pro- 
jectile velocity  and  the  quantity  of  conglobated 
material  parts  ;  the  asteroids  alone,  which  fall 
from  space  into  our  atmosphere,  are  interrupted 
in  their  planetary  round,  and  united  to  a  larger 
planet.  In  the  solar  system,  whose  limits  the 
attractive  force  of  the  central  body  determines, 
comets,  at  the  distance  of  forty-four  times  tho 
distance  of  Uranus  from  the  sun,  are  compelled 
to  return  in  their  elliptical  orbits ;  in  these 
comets  themselves,  indeed,  whose  nuclei,  from 
the  smallness  of  the  masses  they  comprise, 
present  themselves  to  us  in  the  guise  of  flitting 
cosmic  clouds,  these  nuclei,  nevertheless,  bind, 
by  their  attractive  force,  the  very  outermost 
particles  of  the  tail  that  is  streaming  away  at 
the  distance  of  millions  of  miles  from  them. 
The  central  forces,  therefore,  are  the  forming, 
the  fashioning,  and  even  the  preserving  forces 
of  a  system. 

Our  sun,  in  its  relations  to  all  the  returning 
or  circulating,  greater  or  smaller,  denser  or  al- 
most vaporiform  bodies  that  belong  to  it,  may 
be  regarded  as  at  rest ;  yet  does  it  revolve 
around  the  common  centre  of  gravity  of  the 
whole  system,  which,  however,  still  falls  with- 
in itself;  which,  in  other  words,  despite  the 
variable  position  of  the  planets,  still  remains 
attached  to  its  material  bounds.  Altogether 
diflferent  from  this  phenomenon,  is  the  motion 
of  translation  of  the  sun— the  progressive  mo- 
tion of  the  centre  of  gravity  of  the  entire  solar 
system  in  Universal  space.  This  goes  on  with 
such  velocity,  that,  according  to  Bessel,  the 
relative  motions  of  the  sun  and  of  the  61st  star 
in  Cygnus  do  not  amount  to  less  than  834,000 
geographical  miles  in  a  day(").    This  change 


46 


MOTIONS  OF  THE  DOUBLE  STARS. 


of  place  of  the  whole  solar  system  would  re- 
main unknown  to  us,  were  it  not  that  the  won- 
derful perfection  of  modern  astronomical  instru- 
ments for  taking  measurements,  and  the  ad- 
vances of  the  astronomy  of  observation,  ren- 
der our  progress  obvious  towards  distant  stars 
as  towards  objects  on  a  coast  apparently  in 
motion.  The  proper  motion  of  the  61st  star  in 
the  constellation  of  the  Swan,  for  example,  is 
so  considerable,  that  in  the  course  of  700  years 
it  will  have  amounted  to  a  whole  degree. 

The  measure  or  quantity  of  alteration  in  the 
heaven  of  the  fixed  stars — of  alteration  in  the 
relative  positions  of  the  self-luminous  stars  to 
one  another — can  be  determined  with  more  of 
certainty  than  the  phenomenon  itself  can  be 
genetically  explained.  Even  after  we  have  al- 
lowed for  all  that  belongs  to  the  precession  of 
the  equinoxes  and  the  nutation  of  the  earth's  ax- 
is, as  consequences  of  the  influence  of  the  sun 
and  moon  upon  the  spheroidal  figure  of  our  plan- 
et, to  the  propagation  or  aberration  of  light,  and 
to  the  parallax  produced  by  diametrically  oppo- 
site positions  of  the  earth  in  its  orbit  round  the 
sun — when  a  correction  has  been  made  for 
each  and  all  of  these  particulars,  there  is  al- 
ways a  quantity  in  the  remaining  annual  mo- 
tion of  the  fixed  stars,  which  is  the  conse- 
quence of  the  translation  of  the  whole  solar 
system  in  space,  and  which  is  the  consequence 
of  the  proper  and  actual  motion  of  the  stars 
themselves.  The  difficult  numerical  separa- 
tion of  these  two  elements,  of  the  proper  from 
the  apparent  motion,  has  been  made  possible 
by  the  careful  specification  of  the  directions  in 
which  the  motions  of  the  several  stars  take 
place,  and  by  the  reflection  that,  were  all  the 
other  stars  absolutely  at  rest,  they  would  ap- 
pear to  recede  perspectively  from  the  point  to- 
wards which  the  sun  was  moving  in  his  course. 
The  final  result  of  the  investigation,  which  the 
calculus  of  probabilities  confirms,  is  this  :  that 
both  the  stars  and  our  sun  change  their  place  in 
the  Universe.  From  the  admirable  researches 
of  Argelander("),  who  in  Abo  extended  and  ma- 
terially improved  upon  the  labours  begun  by  the 
elder  Herschel  and  Prevost,  it  appears  that  the 
sun  is  in  motion  towards  the  constellation  of 
Hercules,  very  probably  towards  a  point  in  this 
constellation,  which  lies  in  a  combination  of 
537  stars  (for  the  equinox  of  1792-5)  in  257° 
49'  Right  Ascension  ;  -f  28°  49'-7  Declination. 
In  this  class  of  investigations  it  is  always  matter 
of  great  difficulty  to  separate  the  absolute  from 
the  relative  motion,  and  to  determine  what  be- 
longs to  the  solar  system  in  particular  and  alone. 

If  the  non-perspective  proper  motions  of  the 
stars  be  considered,  many  of  them  appear  group- 
wise  opposed  in  their  directions  ;  and  the  data 
hitherto  collected  make  it  at  least  not  necessary 
to  suppose  that  all  the  parts  of  our  astral  sys- 
tem, or  the  whole  of  the  star-islands  which  fill 
the  universe,  are  in  motion  about  any  great, 
unknown,  luminous,  or  non-luminous  central 
mass.  The  longing  to  reach  the  last  or  high- 
est fundamental  cause,  indeed,  renders  the  re- 
flecting faculty  of  man  as  well  as  his  fancy  dis- 
posed to  adopt  such  a  supposition.  The  Stagi- 
rite  himself  has  said — "All  that  is  in  motion 
refers  us  to  a  Mover,  and  it  were  but  an  endless 
adjournment  of  causes  were  there  not  a  prima- 
ry immoveable  Mover"("). 


The  manifold  changes  of  place  exhibited  by 
the  fixed  stars  in  groups,  not  parallactic  mo- 
tions, dependent  on  changes  in  the  position  of 
the  observer,  but  actual  and  ceaseless  motions 
in  universal  space,  reveal  to  us  in  the  most 
incontrovertible  manner,  through  a  particular 
class  of  phenomena,  namely  the  motions  of  the 
double  stars,  and  the  measure  of  their  slower 
or  more  rapid  motions  in  different  parts  of  their 
elliptical  orbits,  the  empire  of  the  laws  of  grav- 
itation beyond  the  limits  of  our  solar  system, 
in  the  remotest  regions  of  creation.  The  curi- 
osity that  is  inherent  in  the  nature  of  man 
needs  not  any  longer  to  seek  satisfaction  upon 
this  field  of  inquiry  in  gratuitous  assumptions, 
in  the  limitless  ideal-world  of  analogies.  By 
the  progress  of  the  astronomy  of  observation 
and  calculation,  it  stands  at  length  even  here 
upon  stable  ground.  It  is  not  so  much  the 
numbers  of  the  double  and  multiple  stars  that 
have  been  discovered  (2,800  to  the  year  1837 !) 
circulating  about  a  centre  of  gravity  lying  be- 
yond the  confines  of  either  or  any  of  them,  that 
excites  our  amazement ;  it  is  the  extension  of 
our  knowledge  of  the  fundamental  force  of  the 
whole  material  world,  the  indications  of  the 
universal  dominion  of  mass-attraction,  that  ar- 
rest us,  and  that  belong  to  the  most  brilliant 
discoveries  of  our  age.  The  time  of  revolution 
of  double  stars  of  different  colours  presents  the 
greatest  imaginable  diversity  ;  it  extends  from 
a  period  of  43  years,  as  in  t}  Coronae,  to  one  of 
several  thousands,  as  in  66  Ceti,  38  Gemino- 
rum,  and  100  Piscis.  Since  Herschel's  meas- 
urements in  1782,  the  nearest  leader  in  the  tri- 
ple system  of  ^  Cancri,  has  now  accomplished 
more  than  a  complete  revolution.  By  a  skilful 
combination  of  observations  of  altered  distan- 
ces and  angles  of  positionC*),  the  elements  of 
the  orbits  of  more  than  one  of  the  double  stars 
have  b^en  discovered — nay,  conclusions  as  to 
the  absolute  distance  of  double  stars  from  the 
earth,  and  comparisons  of  their  masses  with 
the  mass  of  the  sun,  have  even  been  made. 
But  whether  here,  and  in  our  solar  system,  the 
quantity  of  matter  is  the  sole  measure  of  the 
force  of  attraction,  or  whether  specific  attrac- 
tions, not  in  proportion  to  the  mass,  are  at  the 
same  time  efficient,  as  Bessel  first  showed,  is 
a  question  the  solution  of  which  it  remains  with 
late  posterity  to  accomplish("). 

If  we  compare  our  sun,  with  the  other  so- 
called  fixed  stars  in  the  Astral  system  to  which 
we  belong,  with  other  self-luminous  suns,  there- 
fore, we  discover,  in  connection  with  several 
of  them  at  least,  ways  opened  up,  which  ena- 
ble us  to  approximate,  within  certain  extreme 
limits,  to  a  knowledge  of  their  distance,  of 
their  volume,  of  their  mass,  and  of  ihe  rapidity 
with  which  they  change  their  places.  If  we 
assume  the  distance  of  Uranus  from  the  sun, 
at  19  of  the  distances  of  the  earth  from  the  sun 
then  is  the  central  body  of  our  planetary  sys- 
tem 11,900  Uranus  distances  from  the  star  a 
Centauri,  almost  31,300  of  these  distances 
from  61  Cygni,  and  41,600  of  the  same  meas- 
ures from  a  Lyr».  The  comparison  of  the 
volume  of  the  "sun  with  the  volume  of  fixed 
stars  of  the  first  magnitude,  depends  on  an  ex- 
tremely uncertain  optical  element ;  viz.,  the 
apparent  diameter  of  the  fixed  stars.  If,  with 
Herschel,  we  assume  the  apparent  diameter  of 


THE  MILKY  WAYS  OF  STARS  AND  NEBUL.G. 


Arcturus  at  but  one-tenth  part  of  a  second, 
the  actual  diameter  of  this  star  would  still 
come  out  eleven  times  greater  than  that  of  our 
sun(^«).  The  distance  of  the  star  61  Cygni,  for 
the  discovery  of  which  we  are  indebted  to  Bes- 
sel,  has  led  us  approximatively  to  a  knowledge 
of  the  quantity  of  material  particles,  which,  as 
a  double  star,  it  contains.  Although  the  por- 
tion of  the  apparent  path  which  has  been 
passed  through  since  Bradley's  observations, 
is  not  yet  sufficiently  great  to  enable  us  to  con- 
clude with  perfect  certainty  upon  the  true  path, 
and  the  semi-axis  major  of  the  same,  it  has  still 
become  matter  of  probability  to  the  great  as- 
tronomer of  Konigsberg,  '*  that  the  mass  of  the 
double  star  in  question  is  not  materially  either 
less  or  more  than  half  the  mass  of  our  sun(")." 
This  is  the  conclusion  from  actual  measure- 
ment. Analogies  which  are  derived  from  the 
greater  masses  of  the  moon-attended  planets 
of  our  solar  system,  and  from  the  fact  that 
Struve  finds  six  times  as  many  double  stars 
among  the  brighter  fixed  stars  as  among  the 
telescopic  ones,  have  led  other  astronomers  to 
conjecture  that  the  mass  of  the  greater  num- 
ber of  the  twin-stars  is  in  the  mean  greater 
than  that  of  the  sun(^^).  General  results,  how- 
ever, cannot  be  looked  for  in  this  direction  for 
long  years  to  come.  With  reference  to  proper 
motion  in  space,  our  sun,  according  to  Arge- 
lander,  belongs  to  the  class  of  fixed  stars  which 
are  in  rapid  motion. 

The  view  of  the  heavens  inlaid  with  stars, 
the  relative  position  of  the  stars  and  nebulous 
spots,  as  also  the  distribution  of  their  luminous 
masses,'  the  charms  of  the  landscape,  if  I  may 
here  make  use  of  the  expression,  presented  by 
the  firmament  at  large,  will  depend,  in  the 
course  of  millenniums,  relatively  on  the  proper 
actual  motions  of  the  stars  and  nebulae,  on  the 
translation  of  our  solar  system  in  space,  on  the 
bursting  out  of  new  stars,  and  on  the  disap- 
pearance, or  sudden  diminution  in  the  inten- 
sity of  light  in  old  stars;  finally,  and  especially, 
on  the  alterations  which  the  axis  of  the  earth 
experiences  through  the  attraction  of  the  sun 
and  moon.  The  beautiful  stars  of  the  Centaur 
and  the  southern  Cross  will  one  day  become 
visible  in  these  northern  latitudes,  whilst  oth- 
er stars  and  constellations,  Sirius  and  Orion's 
belt,  will  have  sunk.  The  stationary  north 
pole  will  be  indicated  in  succession  by  stars  in 
Cepheus  ((3  and  c),  and  the  Swan  (d),  until, 
after  the  lapse  of  12,000  years,  Vega  in  Lyra 
will  appear  as  the  most  brilliant  of  all  the  pos- 
sible polar  stars.  These  statements  serve  to 
bring  sensibly  before  us  the  vastness  of  the 
motions  which  in  infinitely  small  divisions  of 
time  go  on  incessantly  like  an  eternal  clock — 
the  timepiece  of  the  Universe.  If  we  imagine, 
as  in  a  vision  of  the  fancy,  the  acuteness  of 
oar  senses  preternaturally  sharpened,  even  to 
the  extreme  limit  of  telescopic  vision,  and  in- 
cidents compressed  into  a  day  or  an  hour, 
which  are  separated  by  vast  intervals  of  time, 
everything  like  rest  in  spacial  existence  will 
forthwith  disappear.  We  shall  find  the  innu- 
merable host  of  the  fixed  stars  commoved  in 
groups  in  different  directions  ;  nebulae  drawing 
hither  and  thither,  like  cosmic  clouds ;  the 
milky  way  breaking  up  in  particular  parts,  and 
Its  veil  rent ;  motion  in  every  point  of  the 


vault  of  heaven,  as  on  the  surface  of  the  earth, 
in  the  germinating,  leaf-pushing,  flower-unfold- 
ing organisms  of  its  vegetable  covering.  The 
celebrated  Spanish  botanist,  Cavanilles,  first 
conceived  the  thought  of"  seeing  grass  grow," 
by  setting  the  horizontal  threads  of  a  microme- 
ter attached  to  a  powerful  telescope,  at  one 
time  upon  the  tip  of  the  shoot  of  a  Bambusa, 
at  another  upon  that  of  the  fast-growing  flow- 
ering stem  of  an  American  aloe  (Agave  Ameri- 
cana), precisely  as  the  astronomer  brings  a  cul- 
minating star  upon  the  cross  wires  of  his  in- 
strument. In  the  aggregate  life  of  nature,  or- 
ganic as  well  as  sidereal,  Being,  Maintaining, 
and  Becoming,  are  alike  associated  with  motion. 

The  disruption  of  the  milky  way,  to  which  I 
have  alluded  above,  seems  to  require  a  more 
particular  explanation  in  this  place.  William 
Herschel,  our  safe  and  admirable  guide  in  these 
regions  of  space,  discovered,  by  means  of  his 
star-gau^ings,  that  the  telescopic  breadth  of 
the  milky  way  is  six  or  seven  degrees  greater 
than  it  appears  upon  our  maps  of  the  heavens, 
and  than  the  star-glimmer  indicates  it  to  the  un- 
assisted eye^^').  The  two  brilliant  nodes  in  which 
both  branches  of  the  milky  zone  unite,  in  the 
regions  of  Cepheus  and  Cassiopea,  as  in  those 
of  Scorpio  and  Sagittariu^,  appear  to  exercise  a 
powerful  attraction  upon  the  neighbouring 
stars  ;  betwixt  fi  and  y  Cygni,  however,  in  the 
most  brilliant  region,  of  333,000  stars  that  lie 
in  5°  of  latitude,  one-half  draw  towards  one 
side,  the  other  half  towards  the  opposite  side. 
Here  Herschel  suspects  that  the  stratum  breaks 
up(^°).  The  number  of  the  distinguishable  tel- 
escopic stars  of  the  milky  way — stars  that  are 
broken  by  no  nebulae — has  been  estimated  at 
eighteen  millions.  In  order,  I  will  not  say  to 
give  any  idea  of  the  magnitude  of  this  number, 
but  to  contrast  it  with  something  analogous,  I 
will  remind  the  reader,  that  of  stars  between 
the  1st  and  6th  magnitude,  that  are  visible  to 
the  naked  eye,  there  are  but  some  8,000  scat- 
tered over  the  whole  face  of  the  heavens.  In 
the  barren  astonishment,  excited  by  vastness 
of  number  and  of  space,  without  reference  to 
the  spiritual  nature  or  the  faculty  of  perception 
inherent  in  man,  extremes  in  respect  of  dimen- 
sions of  the  things  that  exist  in  space,  likewise 
me^  and  contrast — the  heavenly  bodies  with 
the  smallest  forms  of  animal  life  :  a  cubic  inch 
of  the  tripoli  of  Bilin,  contains,  according  to 
Ehrenberg,  40,000  millions  of  the  siliceous  cov- 
erings of  the  Galionellse  ! 

To  the  milky  way  of  stars,  to  which,  accord- 
ing to  Argelander's  acute  observation,  many 
of  the  bright  stars  of  the  firmament  appear  re- 
markably to  approximate,  there  is  a  milky  way 
of  nebulae  opposed  almost  at  right  angles.  The 
former,  according  to  Sir  John  Herschel's  views, 
forms  a  ring,  a  detached  and  somewhat  remote 
girdle,  from  the  lenticular  star-island  similai 
to  the  ring  of  Saturn.  Our  planetary  system 
lies  excentrically,  nearer  to  the  region  of  the 
Cross  than  to  the  diametrically  opposite  point 
of  Cassiopea(").  The  form  of  our  astral  stra- 
tum, and  the  parted  ring  of  our  milky  way,  pre- 
sent themselves  reflected  with  wonderful  simi- 
larity in  a  nebula  discovered  by  Messier,  in  1774, 
but  imperfectly  seen  by  him(«2)  The  milky 
way  of  the  nebulae  does  not  properly  belong  to 
our  astral  svstem ;  it  surrounds  this,  without 


48 


PROPAGATION  OF  LIGFIT. 


having  any  physical  connection  with  it,  at  a 
vast  distance,  and  passes  nearly  in  the  form 
of  a  great  circle  through  the  thick  nebulosity 
of  Virgo  (particularly  in  the  northern  wing), 
through  the  Coma  Berenices,  the  Great  Bear, 
the  girdle  of  Andromeda,  and  the  Northern 
Fish.  It  probably  intersects  the  starry  milky 
way  in  Cassiopea,  and  connects  its  poles,  which 
are  poor  in  stars,  made  desolate  by  cluster- 
forming  forces,  at  the  place  where  the  stratum 
of  stars  is  of  least  thickness  in  space(^^). 

It  follows,  from  these  considerations,  that 
whilst  our  cluster  of  stars  bears  traces,  in  its 
diverging  branches,  of  greater  transformations 
effected  in  the  lapse  of  time,  and  strives,  through 
secondary  points  of  attraction,  to  resolve  and 
decompose  itself,  it  is  surrounded  by  two  rings, 
one  vastly  remote,  made  up  of  nebulae,  and  one 
nearer,  consisting  of  stars.  The  latter  ring, 
which  forms  our  milky  way,  is  a  mixture  of 
unnebulous  stars,  on  an  average  from  the  10th 
to  the  11th  magnitude('*),  but,  severally  ob- 
served, of  very  dissimilar  magnitudes,  whilst 
isolated  clusters  of  stars  have  almost  always 
the  character  of  sameness. 

Wherever  the  vault  of  heaven  is  searched 
with  powerful  space-penetrating  telescopes, 
stars,  though  perchance  telescopic  only,  and 
from  the  twentieth  to  the  twenty-fourth  in  or- 
der, or  luminous  nebulae,  are  discovered.  Num- 
bers of  these  nebulae  will  probably  resolve 
themselves  into  stars,  when  they  come  to  be 
examined  with  yet  more  powerful  instruments. 
Our  retina  receives  the  impression  of  single  or 
of  thickly  aggregated  luminous  points  ;  whence, 
as  Arago  has  lately  shown,  totally  different 
photometrical  relations  of  the  sensibility  to 
light  result(*').  The  cosmic  nebulosity,  form- 
less or  fashioned,  generally  diffused,  producing 
heat  by  condensation,  probably  modifies  the 
transparency  of  space,  and  lessens  the  equal 
intensity  of  luminousness  which,  according  to 
Halley  and  others,  must  result,  were  every 
point  of  the  vault  of  heave'n  beset  with  an  end- 
less succession  of  stars  in  the  direction  of  its 
depthC^).  The  assumption  of  any  such  con- 
tinuous inlaying  of  stars  contradicts  observa- 
tion ;  which,  in  fact,  shows  us  vast  starless 
regions — openings  in  heaven,  as  William  Her- 
schel  calls  them — one  in  Scorpio,  four  decrees 
in  breadth,  and  another  in  the  loin  of  Ophiucus  ; 
in  the  vicinity  of  both  of  which,  and  close  to 
their  edges,  we  discover  resolvable  nebulae. 
That  which  is  situated  on  the  western  edge  of 
the  opening  in  Scorpio,  is  one  of  the  richest 
and  most  thickly  set  clusters  of  small  stars 
that  ornament  the  heavens.  Herschel  himself 
ascribes  the  openings,  the  starless  regions  in 
the  sky,  to  the  attraction  and  cluster-forming 
force  of  these  marginal  groups(^').  "  They  are 
portions  of  our  star-stratum,"  says  he,  in  the 
fine  liveliness  of  his  style,  "  which  have  suffer- 
ed great  desolations  from  time."  If  we  picture 
to  ourselves  the  telescopic  stars  that  lie  one 
behind  another,  as  forming  a  starry  can'opy  in- 
vesting the  whole  of  the  visible  vault  of  heaven, 
then,  I  believe,  are  those  starless  regions  of 
the  Scorpion  and  Serpent-bearer,  to  be  regard- 
ed as  tubes,  through  which  we  see  into  the 
farthest  regions  of  space.  The  layers  of  the 
canopy  are  interrupted  ;  other  stars,  indeed, 
may  lie  within  the  gaps,  but  they  are  unattain- 


able to  our  instruments.  The  sight  of  fiery 
meteors  had  already  led  the  ancients  to  the 
idea  of  clefts  and  chasms  in  the  canopy  of 
heaven  ;  but  these  were  regarded  as  passing 
or  temporary  only.  Instead  of  being  dark,  they 
were  luminous  and  fiery,  by  reason  of  the 
translucent  igneous  ether  that  lay  behind 
them('^).  Derham,  and  even  Huyghens,  appear 
not  indisposed  to  explain  the  mild  light  of  neb- 
ulae on  some  such  grounds(*'). 

When  we  compare  the  brilliant,  and  on  an 
average  certainly  nearer,  stars  of  the  first  mag- 
nitude, with  the  telescopic  or  resolvable  nebu- 
lae, and  contrast  the  nebulous  stars  with  the 
wholly  unresolvable  nebulae  (with  the  one  in 
Andromeda,  for  example),  or  even  with  the  so- 
called  planetary  nebulae,  in  the  contemplation, 
of  distances  so  different,  plunged,  as  it  were, 
in  the  boundlessness  of  space,  we  have  a  fact 
revealed  to  us  by  the  world  of  phenomena,  and 
the  reality,  which,  in  causal  connection  with  it, 
always  forms  its  substrate — the  fact  of  The 
Propagation  of  Light.  The  rate  of  this  prop- 
agation, according  to  Struve's  latest  research- 
es, is  41,518  geographical  [166,072  English] 
miles  in  a  second ;  nearly  a  million  times 
greater,  therefore,  than  the  rate  of  sound. 
From  what  we  know  through  the  measure- 
ments of  Maclear,  Bessel,  and  Struve,  of  the 
parallaxes  and  distances  of  three  fixed  stars  of 
very  unequal  magnitudes — aCentauri,6lCygni, 
and  a  Lyrae — a  ray  of  light  requires  3  years, 
9i  years,  and  12  years,  to  reach  us  from  these 
celestial  bodies  severally.  In  the  short  but 
remarkable  period  from  1572  to  1604,  from  Cor- 
nelius Gemma  and  Tycho  to  Kepler,  three  new 
stars  blazed  suddenly  forth  in  Cassiopea,  in 
Cygnus,  and  in  the  foot  of  Ophiucus.  The 
same  phenomenon  showed  itself  in  1570  in  the 
constellation  of  the  Fox  ;  but  here  it  recurred 
several  times.  In  the  very  latest  times,  since 
1837,  Sir  John  Herschel  during  his  sojourn  at 
the  C!ape  of  Good  Hope  observed  the  star  ij  of 
the  constellation  Argo  increase  in  brilliancy 
from  a  star  of  the  second  magnitude  to  one  of 
the  first(50).  Such  incidents  in  the  universe 
belong,  however,  in  their  historical  reality,  to 
other  times  than  those  in  which  the  phenome- 
na of  light  notify  their  commencement  to  the 
inhabitants  of  the  earth  ;  they  are  the  voices  of 
the  past  which  reach  us.  It  has  been  well 
said,  that  with  our  mighty  telescopes  we  pen- 
etrate at  once  into  space  and  into  time.  We 
measure  the  former  by  the  latter,  the  latter  by 
the  former ;  an  hour  of  travel  for  the  ray  of 
light  is  one  hundred  and  forty-eight  millions  of 
geographical  miles  passed  through.  Whilst  the 
dimensions  of  the  universe  are  expressed  in 
the  theogony  of  Hesiod  by  the  fall  of  heavy 
bodies — "  the  brazen  anvil  falls  in  no  more  than 
nine  days  and  nine  nights  from  heaven  to 
earth"  —  Herschel,  the  Father ("),  believed 
"  that  the  light  of  the  farthest  nebulae,  which 
his  forty-feet  reflector  showed  him,  took  about 
two  millions  of  years  to  reach  the  earth." 
Much,  therefore,  has  long  disappeared,  much 
has  already  been  otherwise  arranged,  before  it 
becomes  visible  to  us.  The  aspect  of  the  starry 
heavens  presents  us  with  evidences  of  diversity 
in  point  of  time  ;  and  diminish  as  we  will  the 
millions  or  even  thousands  of  years  which 
serve  us  as  measures  for  the  distance  of  the 


TERRESTRIAL  SPHERE. 


tlTiresolvable  nebulae  with  their  soft  lustre,  and 
of  the  resolvable  nebulee  with  their  twilight 
gleamings,  bring  them  as  close  to  us  as  we 
may,  it  still  remains  more  than  probable,  from 
the  knowledge  we  have  of  the  velocity  of  light, 
that  the  light  of  the  remote  celestial  bodies 
offers  the  oldest  sensible  evidence  of  the  exist- 
ence of  matter.  So  rises  reflecting  man,  from 
his  stance  on  simple  premises,  to  solemn  and 
noble  views  of  natural  formations  to  the  deep 
fields  of  space,  where  flooded  with  everlasting 
light— 

"  Myriads  of  worlds  spring  up  like  the  grass  of  night."(92) 

From  the  region  of  celestial  formations,  from 
the  children  of  Uranos,  we  now  descend  to  the 
narrower  domain  of  terrestrial  forces,  to  the 
children  of  Gaea.  A  mysterious  band  surrounds 
and  binds  together  both  classes  of  phenomena. 
In  the  import  of  the  old  Titanian  Mythus  ("), 
all  the  powers  of  the  universal  life,  the  whole 
mighty  order  of  nature,  is  connected  with  the 
co-operation  of  the  heavens  and  the  earth. 
And,  indeed,  if  the  terrestrial  ball,  like  all  the 
other  planets,  belongs,  in  virtue  of  its  origin, 
to  the  central  body,  the  sun,  and  to  its  atmo- 
sphere, once  parted  into  nebulous  rings,  an  in- 
tercourse is  still  kept  up,  by  means  of  light  and 
radiant  heat,  with  this  neighbouring  sun,  as 
with  all  the  farther  suns  that  sparkle  in  the 
firmament.  The  diversity  of  the  mass  of  these 
influences  must  not  restrain  the  physical  as- 
tronomer from  referring  in  a  natural  picture  to 
the  connection  and  the  dominion  of  common 
and  similar  forces.  A  small  fraction  of  the 
terrestrial  heat  belongs  to  that  of  the  universal 
space  through  which  our  planetary  system  pur- 
sues its  way,  and  which,  the  product  of  all  the 
light-radiant  stars,  is  nearly  of  the  mean  tem- 
perature of  our  icy  circumpolar  regions,  accord- 
ing to  Fourier.  But  what  it  is  that  excites  the 
light  of  the  sun  more  powerfully  in  the  atmo- 
sphere and  upper  strata  of  the  earth — how, 
producing  heat,  it  gives  rise  to  electrical  and 
magnetical  currents — how  it  magically  kindles 
and  beneficially  feeds  the  flame  of  life  in  the 
organic  forms  that  people  the  earth — all  this 
will  form  the  subject  of  our  considerations  by 
and  by. 

Whilst  we  here  apply  ourselves  exclusively 
to  the  telluric  sphere  of  nature,  then,  we  shall 
first  take  a  glance  at  the  relative  proportions 
of  the  Solid  and  the  Fluid,  at  the  figure  of  the 
earth,  its  mean  density,  and  the  partial  distri- 
bution of  this  density  in  the  interior  of  the 
planet ;  at  the  contained  heat,  and  the  mag- 
netic charge  of  the  earth.  These  relations  in 
respect  of  space,  and  these  forces  inherent  in 
matter,  lead  to  the  reaction  of  the  interior  upon 
the  exterior  of  our  earth ;  they  lead  through 
the  special  consideration  of  an  universally  dif- 
fused natural  force  —  sub-terrestrial  heat — to 
the  not  always  merely  dynamic  phenomena  of 
earthquakes  in  circles  of  concussion  of  various 
extent,  to  the  outbreak  of  hot  springs,  and  the 
mightier  operations  of  volcanic  processes.  The 
crust  of  the  earth  shaken  from  below,  now  in 
pulses,  suddenly  and  violently,  now  smoothly 
and  continuously,  and  therefore  scarcely  per- 
ceptibly, alters  in  the  course  of  centuries  the 
relations  in  point  of  elevation  between  the  Dry 
and  the  surface-level  of  the  Fluid  ;  nay,  the 
form  of  the  bed  of  the  ocean  itself.  There  are, 
G 


at  the  same  time,  either  temporary  cracks,  or 
more  permanent  openings  formed,  through 
which  the  interior  of  the  earth  comes  into  re- 
lationship with  the  atmosphere.  Welling  up 
from  unknown  depths,  molten  masses  flow  in 
narrow  streams  along  the  slopes  of  the  mount- 
ains, here  precipitously,  there  slowly,  gently, 
until  the  fiery  spring  runs  dry,  and  the  lava, 
emitting  vapours,  solidifies  beneath  a  crust 
which  it  has  formed  for  itself  New  rocky 
masses  then  arise  before  our  eyes,  whilst  older 
ones,  already  formed  by  Plutonic  forces,  suffer 
change,  rarely  through  immediate  contact,  more 
frequently  from  their  vicinity  to  heat-radiating 
centres  or  masses.  In  situations  where  there 
is  no  eruption,  crystalline  particles  are  still  dis- 
placed, and  then  combined  into  denser  textures. 

The  waters  present  us  with  formations  of  a 
totally  different  nature  :  aggregations  of  the  re- 
mains of  plants  and  animals  ;  earthy,  creta- 
ceous, and  clayey  deposits  ;  conglomerates  of 
finely  pulverized  mountain  species,  overlaid  by 
layers  of  siliceous-shelled  infusoria,  and  bone- 
containing  drift,  the  resting  place  of  the  re- 
mains of  animals  that  peopled  a  former  world. 
All  that  we  see  engendered  in  such  variety  of 
ways  beneath  our  eyes,  and  arranged  in  layers, 
all  that  we  observe  so  variously  cast  down, 
and  bent,  and  raised  again,  under  the  influence 
of  opposing  pressure  and  volcanic  force,  leads 
the  reflective  observer,  who  yields  himself  to 
the  guidance  of  simple  analogies,  to  the  com- 
parison of  the  Present  with  times  that  have 
long  gone  by.  Through  combination  of  actual 
phenomena,  through  ideal  amplification  in  ref- 
erence to  the  extent  as  well  as  to  the  mass  of 
the  forces  in  operation,  we  reach  at  length  the 
long-desired,  the  dimly-imagined,  but  first,  in 
the  course  of  the  last  century,  firmly-founded 
domain  of  geognosy. 

It  has  been  acutely  observed,  that,  "  with  all 
our  looking  through  powerful  telescopes,  we 
actually  know  more  of  the  interior  of  other 
planets  than  of  their  exterior  — the  moon,  per- 
haps, excepted."    They  have  been  weighed, 
and  their  volumes  have  been  measured  ;  their 
masses  and  their  densities  are  known,  in  either 
case — thanks  to  the  progress  of  the  astronomy 
of  observation  and  calculation — with  still  in- 
creasing numerical  certainty.    Over  their  phys- 
ical constitution  there  hangs  a  deep  obscurity. 
It  is  only  in  our  own  earth  that  immediate  vi- 
cinity brings  us  into  contact  with  the  various 
elements  of  organic  and  inorganic  creation. 
Here  the  garner  of  matter,  in  its  multifarious 
diversity,  in  its  endlessness  of  admixture  and 
modification  and  change,  in  the  ever-varying 
play  of  forces  evoked,  presents  the  spirit  with 
its  proper  food :  the  joys  of  investigation,  the 
unbounded  field  of  observation,  which,  cultiva- 
ting and  strengthening  the  faculty  of  thought, 
gives  to  the  intellectual  sphere  of  man's  exist- 
ence a  portion  of  its  grandeur,  of  its  sublimity. 
The  world  of  sensible  phenomena  reflects  it- 
self in  the  deeps  of  the  ideal  world :  the  abun- 
dance of  nature,  the  mass  of  things  discernible, 
passes  gradually  into  the  domain  of  knowledge 
approved  by  reason. 

And  here,  again,  I  touch  upon  an  advantage 
to  which  I  have  already  alluded  several  times 
—the  advantage  of  that  knowledge  which  has 
a  home  origin,  and  of  which  the  possibility  is 


50 


TERRESTRIAL  SPHERE. 


most  intimately  connected  with  our  earthly  ex- 
istence. The  description  of  the  heavens,  from 
the  far-gleaming  nebulous  stars  (with  their 
suns)  down  to  the  central  body  of  our  own 
system,  we  found  limited  to  such  general  con- 
ceptions as  volume  and  quantity  of  matter.  No 
vital  movement  is  there  revealed  to  our  senses. 
It  is  only  after  resemblances,  often  after  fanci- 
ful combinations,  that  we  arrive  at  conjectures 
as  to  the  specific  nature  of  matters  of  different 
kinds,  as  to  its  [presence  or]  absence  in  this 
or  in  that  planetary  body.  The  heterogeneous- 
ness  of  matter,  its  chemical  diversity,  and  the 
regular  forms  into  which  its  particles  arrange 
themselves,  as  crystals  and  granules ;  its  re- 
lations to  the  penetrating  deflected  or  decom- 
pounded waves  of  light,  to  radiating,  transmit- 
ted, or  polarized  heat,  to  the  brilliant,  or  invis- 
ible, but  not  on  that  account  less  powerful, 
phenomena  of  electro-magnetism — all  this  vast 
treasury  of  physical  knowledge,  which  so  ex- 
alts our  views  of  nature,  we  owe  to  the  sur- 
face of  the  planet  we  inhabit,  and  to  the  solid 
rather  than  the  fluid  element  in  its  constitution. 
How  this  knowledge  of  natural  things  and  nat- 
ural forces,  how  the  measureless  variety  of  ob- 
jective perceptions,  calls  forth  the  intellectual 
activity  of  our  kind,  and  hastens  our  progress 
in  improvement,  has  been  already  observed 
upon  above.  These  relations  as  little  require 
farther  development  in  this  place,  as  the  en- 
chainment of  the  causes  of  that  material  force 
which  the  control  of  a  portion  of  the  elements 
has  given  to  particular  nations. 

If  it  was  imperative  on  me  to  direct  atten- 
tion to  the  difference  which  exists  betwixt  the 
nature  of  our  telluric  knowledge,  and  our  knowl- 
edge of  heavenly  space  and  its  contents,  so  is 
it  also  necessary  for  me  to  indicate  the  narrow- 
ness of  the  field  from  which  the  whole  of  our 
knowledge  of  the  heterogeneousness  of  matter 
is  derived.  This  field  is  somewhat  inappropri- 
ately called  THE  CRUST  OF  THE  EARTH ;  it  is  the 
thickness  of  the  strata  that  lie  nearest  the  sur- 
face of  our  planet,  and  that  are  exposed  in  deep 
chasm-like  valleys,  or  by  the  labour  of  man  in 
his  boring  and  mining  operations.  These  works 
scarcely  attain  a  perpendicular  depth  of  more 
than  two  thousand  feet  (less  than  JLth  of  a  Ger- 
man mile)  below  the  level  of  the  sea  ;  conse- 
quently only  ^^^ji^th  of  the  semidiameter  of  the 
earthC*).  The  crystalline  masses  which  are 
ejected  by  active  volcanoes,  and  which  are 
mostly  of  the  same  nature  as  the  rocky  matters 
of  the  surface,  come  from  unknown,  certainly 
sixty  times  greater  absolute  depths  than  those 
which  the  labours  of  man  have  reached.  In 
situations  where  seams  of  coal  dip  to  rise  again 
at  distances  determinable  by  accurate  measure- 
ments, it  is  easy  to  ascertain  the  depth  of  the 
basin  in  which  the  strata  lie.  In  this  way  we 
learn,  that  in  some  places  (Belgium,  for  exam- 
ple) the  coal  measures,  together  with  the  or- 
ganic remains  of  a  former  world,  which  they 
contain,  frequently  lie  more  than  five,  or  even 
six,  thousand  feet  below  the  present  level  of 
the  sea(") :  aye,  that  the  mountain  limestone 
and  Devonian  basin-shaped  bent  strata,  descend 
even  to  twice  that  depth.  If  we  now  contrast 
these  subterraneous  basins  with  the  mountain 
summits  which  have  hitherto  been  held  as  the 
highest  portions  of  the  uplifted  crust  of  the 


earth,  we  obtain  a  distance  of  37,000  feet,  it 
nearly  ^^th  of  the  earth's  semidiameter  lie- 
twixt  the  point  of  extreme  descent  and  that  of 
highest  elevation.  This,  in  the  perpendicular 
dimension  and  space-filling  superposition  of 
rocky  strata,  would  still  be  the  only  theatre  of 
geognostic  investigation,  even  did  the  general 
surface  of  the  earth  reach  the  height  of  Dhaw- 
alagiri,  in  the  Himalaya  chain,  or  of  Sorata,  in 
Bolivia.  All  that  lies  under  the  sea  level  deep- 
er than  the  basins  referred  to  above,  than  the 
works  of  man,  than  the  bottom  of  the  ocean, 
attained  in  various  places  with  the  plumb-line 
(Sir  James  Ross  sounded  with  25,400  feet  of 
line,  without  reaching  the  bottom),  is  even  as 
much  unknown  to  us  as  is  the  interior  of  the 
other  planets  belonging  to  our  system.  We 
also  know  but  the  mass  of  the  whole  earth  and 
its  mean  density,  compared  with  the  superior 
and  to  us  solely  accessible  strata.  Where  all 
knowledge  of  the  chemical  and  mineralogical 
natural  constitution  of  the  interior  of  the  earth 
fails  us,  we  are  again  thrown  upon  conjecture, 
just  as  we  are  with  reference  to  the  farthest 
bodies  that  revolve  about  the  sun.  We  can  de- 
termine nothing  with  certainty  upon  the  depth 
at  which  the  rocky  strata  of  the  crust  of  the 
globe  should  be  regarded  as  existing  in  a  tena- 
cious softened  state,  or  as  a  molten  liquid ; 
upon  the  cavities  filled  with  elastic  vapours ; 
upon  the  condition  of  liquids  when  they  are 
heated  red-hot  under  enormous  pressures  ;  or 
upon  the  law  of  the  increment  of  density  from 
the  surface  of  the  earth  down  to  its  centre. 

The  consideration  of  the  increment  of  tem- 
perature of  the  interior  of  our  planet  with  in- 
creasing depths,  and  of  the  reaction  of  the  in- 
terior upon  the  surface,  has  led  us  to  the  ex- 
tensive series  of  volcanic  phenomena.  These 
manifest  themselves  as  earthquakes,  effusions 
of  gaseous  fluids,  hot  springs,  mud-volcanoes, 
and  lava-streams,  from  craters  ;  the  influence 
of  elastic  force  is  also  shown  in  unquestionable 
alterations  in  the  level  of  the  general  surface. 
Extensive  levels,  variously-partitioned  conti- 
nents, are  upheaved  or  sunk  ;  the  solid  is  part- 
ed from  the  fluid ;  but  the  ocean  itself,  trav- 
ersed by  hot  and  cold  currents  that  flow  through 
it  like  rivers,  congeals  at  either  pole,  and  sets 
into  solid  rocky  masses,  here  stratified  and 
immoveable,  there  broken  into  moveable  packs 
and  islets.  The  boundaries  of  the  sea  and 
land,  of  the  fluid  and  the  solid,  are  variously 
and  frequently  changed.  Plains,  too,  oscillate 
upwards  and  downwards.  After  the  elevation 
of  continents,  long  clefts  or  chasms  took  place, 
mostly  parallel  to  one  another,  and  then,  in  all 
probability,  at  similar  epochs  in  time,  and 
through  them,  were  mountain-chains  upheav- 
ed :  salt  pools  and  great  inland  seas,  which 
were  long  inhabited  by  the  same  creatures, 
were  forcibly  separated.  The  fossil  remains 
of  shells  and  zoophytes  bear  witness  to  their 
original  connection.  And  so  we  come,  follow- 
ing the  relative  dependence  of  phenomena,  from 
the  consideration  of  the  fashioning  forces,  work- 
ing deep  in  the  interior  of  the  earth,  to  that 
which  shakes  and  shatters  its  upper  crust,  and 
which,  through  the  force  of  elastic  vapours, 
flows  out  as  a  molten  stream  of  earth  (lava) 
from  open  fissures. 

The  same  forces  that  uplifted  the  Andes  and 


FIGURE  OF  THE  EARTH. 


Himalaya  chains,  even  to  the  regions  of  eter- 
nal snow,  produced  new  admixtures  and  new 
textures  in  the  rocky  masses,  and  altered  the 
strata  which  had  been  thrown  down  at  earlier 
periods,  from  waters  teeming  with  life  and  or- 
ganized matters.  We  recognize  here  the  suc- 
cession of  formations,  separated  according  to 
their  age  and  superposed,  in  their  dependence 
upon  the  alterations  in  form  of  the  surface, 
upon  the  dynamical  relations  of  the  upheaving 
forces,  upon  the  chemical  actions  of  outbreak- 
ing vapours  upon  the  fissures. 

The  form  and  distribution  of  continents — in 
other  words,  of  the  dry  land— of  that  portion  of 
the  crust  of  the  earth  which  is  susceptible  of 
the  vigorous  evolution  of  vegetable  life,  stands 
in  intimate  relationship,  and  potential  recipro- 
city of  action,  with  the  all-surrounding  sea.  In 
this  the  organizing  force  is  almost  wholly  ex- 
pended upon  the  animal  world.  The  liquid  el- 
ement, again,  is  invested  by  the  gaseous  atmo- 
sphere, an  aerial  ocean,  into  which  the  mount- 
ain chains  and  lofty  plateaus  of  the  dry  land 
rise  like  reefs  and  shoals,  induce  a  vast  variety 
of  currents  and  changes  of  temperature,  collect 
moisture  from  the  region  of  the  clouds,  and  by 
the  running  streams  that  furrow  their  sides, 
spread  motion  and  life  over  all. 

If  the  Geography  of  Plants  and  Animals  de- 
pends on  these  intricate  contrasts  in  the  distri- 
bution of  sea  and  shore,  in  the  formation  of  the 
surface,  and  the  direction  of  isothermal  lines 
(or  zones  of  mean  annual  temperature),  so,  on 
the  other  hand,  are  characteristic  differences 
in  the  races  of  men  and  their  relative  numeri- 
cal distribution  over  the  face  of  the  earth — the 
last  and  noblest  object  of  a  physical  description 
of  the  globe — influenced  not.  by  these  natural 
relations  alone,  but  at  the  same  time,  and  es- 
pecially by  progress  in  civilization,  in  mental 
improvement,  in  political  superiority  grounded 
upon  national  cultivation.  Some  races,  cling- 
ing to  the  soil,  are  supplanted  and  annihilated 
by  the  dangerous  vicinity  of  more  politic  com- 
munities :  a  faint  historical  trace  is  soon  all 
that  remains  of  them  ;  other  races,  in  numbers 
not  the  strongest,  put  forth  upon  the  liquid  ele- 
ment ;  and  almost  omnipresent  by  means  of 
this,  have  they  alone,  though  late,  attained  to 
a  general  graphical  knowledge  of  the  surface, 
of  all  the  seaboards  at  least,  of  our  planet  from 
pole  to  pole. 

Here,  then,  and  before  I  have  touched  upon 
the  individual,  in  our  natural  picture  of  the 

TELLURIC  SPHERE  OF  PHENOMENA,  I  haVO  ShOWU 

in  General,  how  from  considerations  on  the  form 
of  the  globe,  and  on  the  ceaseless  manifesta- 
tions of  force  in  its  electro-magnetism  and  sub- 
terranean heat,  the  relations  of  the  earth's  sur- 
face in  horizontal  extension  and  elevation,  the 
geognostic  type  of  mineral  formations,  the  realm 
of  the  ocean,  and  of  the  atmosphere  with  its 
meteorological  processes,  the  geographical  dis- 
tribution of  plants  and  animals,  and,  finally,  the 
physical  gradations  of  the  human  race,  alone, 
but  in  all  circumstances  susceptible  of  spiritual 
culture,  may  be  comprised  in  one  and  the  same 
contemplative  survey.  This  unity  of  contem- 
plation presupposes  an  enchainment  of  phenom- 
ena according  to  their  intimate  connections. 
A  mere  tabular  arrangement  of  phenomena 
Vfi  )uld  not  accomplish  the  purpose  I  prescribed 


myself;  it  does  not  satisfy  the  want  of  that 

COSMICAL  REPRESENTATION  which  thC  aspCCt  of 

nature  by  sea  and  land,  the  diligent  study  of 
formations  and  forces,  and  the  lively  impression 
of  a  natural  whole,  which  has  been  made  upon 
my  mind  in  the  course  of  my  travels  in  various 
and  dissimilar  climates  of  the  globe.  Much 
that  in  this  essay  is  so  exceedingly  defective, 
with  the  accelerated  rate  at  which  knowledge 
of  all  the  departments  of  physical  science  ad- 
vances, will  probably  ere  long  be  corrected  and 
filled  up.  It  lies,  indeed,  in  the  path  of  devel- 
opment which  every  science  pursues,  that  that 
which  long  stood  isolated,  becomes  connected 
by  degrees  and  subjected  to  higher  laws.  I  but 
point  out  the  empirical  way,  along  which  I, 
and  many  minded  like  myself,  advance,  full  of 
expectation  that  "Nature,"  as  Plato  tells  us 
Socrates  once  desired,  "  shall  have  interpreta- 
tion according  to'reason"('*). 

Our  account  of  terrestrial  phenomena,  in  their 
principal  features,  must  begin  with  the  form 
and  relations  in  space  of  our  planet.  And  here, 
too,  it  may  be  said,  that  not  merely  does  the 
mineral  constitution,  the  crystalline,  the  gran- 
ular, the  dense  masses  filled  with  petrefactions, 
but  also  the  geometrical  figure  of  the  earth  it- 
self, bear  witness  to  the  mode  of  its  origin  ;  its 
figure  is  its  history.  An  elliptical  spheroid  of 
rotation  indicates  a  once  soft  or  semi-fluid  mass. 
To  the  oldest  geognostic  incidents,  writ  down, 
and  clearly  legible  to  the  understanding  eye,  in 
the  book  of  nature,  belongs  the  flattening  [of 
the  poles  of  the  earth],  and  to  adduce  another 
and  nearly  related  instance,  the  perpetual  di- 
rection of  the  greater  axis  of  the  moon's  spheroid 
towards  the  earth ;  i.  e.  the  accumulation  of  mat- 
ter upon  that  half  of  the  moon  which  we  see,  and 
which  determines  the  relation  between  the  peri- 
od of  rotation  and  that  of  revolution.  And  the 
same  law  extends  to  the  oldest  formative  epochs 
of  all  the  satellites.  "  The  mathematical  figure 
of  the  earth  is  that  which  it  would  have  were 
its  surface  covered  with  water  in  a  state  of  re- 
pose ;"  to  this  are  referred  all  geodetic  meas- 
urements of  degrees  reduced  to  the  sea-level. 
From  this  mathematical  surface  of  the  earth, 
the  physical  one,  with  all  its  accidents  and  in- 
equalities of  the  solid,  difFers(").  The  whole 
figure  of  the  earth  is  determined  when  the  quan- 
tity of  oblateness  and  the  magnitude  of  the 
equatorial  diameter  are  known.  To  obtain  a 
complete  picture  of  the  figure,  however,  it  were 
necessary  to  have  measurements  in  two  direc- 
tions perpendicular  to  each  other. 

Eleven  pneasurements  of  degrees,  or  deter- 
minations of  the  curvature  of  the  earth's  sur- 
face in  different  countries,  of  which  nine  belong 
exclusively  to  the  present  century,  have  given 
us  accurate  information  on  the  dimensions  oi 
the  earth,  which  Pliny  long  ago  designated  as 
"  a  point  in  the  infinity  of  space*'('«).  If  these 
measurements  do  not  agree  in  the  curvature  of 
diflferent  meridians  under  the  same  degrees  of 
latitude,  this  very  circumstance  vouches  for 
the  sufficiency  of  the  instruments  and  of  the 
methods  employed,  for  the  accuracy  of  partial 
results  true  to  nature.  The  inference  from 
the  increase  of  attractive  force  proceeding  from 
the  equator  towards  the  pole,  in  reference  to 
the  figure  of  a  planet,  depends  on  the  distribu- 


59 


FIGURE  OF  THE  EARTH. 


tion  of  density  in  its  exterior.  If  Newton,  upon 
theoretical  grounds,  and  also  excited  to  the  in- 
quiry by  Cassini's  discovery  of  the  flattening 
of  Jupiter's  poles  in  1666("),  determines  the 
flattening  of  the  earth  as  a  homogeneous  mass 
at  2 jTF^h,  in  his  immortal  work,  the  Principia, 
actual  admeasurements,  under  the  influence  of 
the  new  and  more  perfect  analysis,  have  shown 
that  the  oblateness  of  the  earth's  spheroid,  the 
density  of  the  strata  being  assumed  to  go  on 
increasing  towards  the  centre,  amounts  to  3^,^th 
very  nearly. 

Three  methods  have  been  employed  to  deter- 
mine fundamentally  the  curvature  of  the  earth's 
surface  :  measurements  of  degrees,  pendulum 
experiments,  and  certain  inequalities  of  the 
moon's  orbit.     Thg  first  of  these  methods  is  an 
immediate  geometro-astronomical  one  ;  in  the 
other  two,  conclusions  are  drawn  from  care- 
fully observed  motions,  in  regard  to  the  forces 
which  occasion  these  motions,  and,  from  these 
forces,  in  regard  to  their  causes,  viz.  the  ob- 
lateness of  the  earth  in  its  polar  axis.     I  have 
here,  in  the  general  picture  of  nature,  referred 
exclusively  to  the  application  of  these  methods, 
because  their  certainty  reminds  us  forcibly  of 
the  intimate  concatenation  of  natural  phenom- 
ena in  their  forms  and  forces,  because  this  ap- 
plication has  itself  become  the  happy  occasion 
of  improving  all  our  instruments,  whether  op- 
tical or  those  that  are  employed  in  the  meas- 
urement of  space  or  of  time — the  very  founda- 
tion of  astronomy  and  mechanics  in  reference 
to  the  moon's  motions,  and  the  determination 
of  the  resistance  which  the  oscillation  of  the 
pendulum  experiences — and  because  it  has  even 
served  to  open  up  peculiar  and  untrodden  paths 
to  analysis.     After  the  researches  on  the  par- 
allax of  the  fixed  stars,  which  led  to  the  dis- 
covery of  aberration  and  nutation,  the  history 
of  the  sciences  presents  us  with  no  problem 
second  in  importance  to  that  in  which  the  re- 
sult sought  is  a  knowledge  of  the  mean  oblate- 
ness of  the  earth,  and  the  certainty  that  the 
figure  of  our  planet  is  not  a  regular  one.     In 
none  of  the  long  and  laborious  ways  by  which 
the  goal  is  attained  in  scientific  investigations, 
is  higher  general  cultivation,  or  more  perfect 
knowledge  of  mathematical  and  astronomical 
science  required  than  in  this.     The  comparison 
of  eleven  measurements  of  degrees,  among 
which  three  extra  European — the  old  Peruvian 
one,  and  two  East-Indian— are  included,  cal- 
culated in  conformity  with  the  severe  theoret- 
ical requirements  of  Bessel,  has  given  a^^th 
as  the  measure  of  oblateness  of  the  polar  di- 
ameter of  the  earth('"°).     From  this  it  appears 
that  the  polar  semidiameter  is  10,938  toises^ 
about  2j  geographical  miles,  shorter  than  the 
equatorial  semi-diameter  of  the  elliptical  sphe- 
roid of  rotation.     The  bulging  under  the  equa- 
tor, therefore,  in  consequence  of  the  curvature 
of  the  surface  of  the  spheroid  in  the  direction 
of  gravity,  comes  to  something  more  than  4^- 
times  the  height  of  Mont  Blanc,  only  2^  times 
the  probable  height  of  Dhawalagiri,  in  the  Him- 
alaya range.     The  moon's  equation,  in  other 
words  the  perturbation  in  longitude  and  lati- 
tude of  the  moon,  from  the  latest  researches  of 
Laplace,  give  nearly  a  similar  degree  of  oblate- 
ness as  the  measurement  of  degrees  of  the  me- 


ridian—viz. jh^ih.  Experiments  with  the  pen- 
dulum indicate  a  much  more  considerable 
amount  of  flattening— viz.  2  5^th(^"). 

Galileo,  when  a  boy,  during  divine  service^ 
and  somewhat  inattentive  to  the  matter  in 
hand,  as  it  would  seem,  perceived  that  the 
whole  height  of  a  roof  might  be  ascertained 
from  the  dissimilar  times  in  which  chandeliers, 
suspended  at  different  elevations,  oscillated  j 
but  he  certainly  did  not  imagine  that  the  pendu- 
lum would  one  day  be  carried  from  pole  to 
pole,  with  a  view  to  determine  the  figure  of  the 
earth  ;  or  rather  to  afford  evidence  of  the 
length  of  the  seconds-pendulum  being  affected 
by  strata  of  the  earth  of  unequal  density.  These 
local  attractions  are  complex,  undoubtedly ;  but 
over  extensive  districts  of  country  they  show 
themselves  almost  identical  in  point  of  amount. 
These  geognostic  relations  of  an  instrument 
for  the  measurement  of  time;  this  peculiar 
property  of  the  pendulum  to  act  a»  a  plumb-line, 
and  give  us  intelligence  of  the  unseen  deep, 
even  in  volcanic  islands('**),  and  on  the  acclivi- 
ties of  uplifted  continental  mountain  chains(*"), 
to  indicate  dense  masses  of  basalt  and  melam- 
phyx  instead  of  caverns,  combine  to  render  dif- 
ficult, despite  the  wonderful  simplicity  of  the 
method,  the  attainment  of  any  general  result 
as  to  the  figure  of  the  earth  from  observations 
on  the  oscillation  of  the  pendulum.  Even  in 
the  astronomical  part  of  the  measurement  of  a 
degree  of  latitude,  the  occurrence  of  mountain 
masses,  or  of  denser  strata  in  the  ground,  have 
a  disturbing  and  prejudicial  influence,  although 
not  to  the  same  extent  as  in  pendulum  experi- 
ments. 

As  the  figure  of  the  earth  exerts  a  powerful 
influence  on  the  motion  of  other  planetary  bod- 
ies, especially  on  that  of  her  immediate  satel- 
lite, so,  on  the  other  hand,  does  the  very  per- 
fect knowledge  we  possess  of  the  motion  of 
the  moon  enable  us  to  draw  counter-conclu- 
sions in  regard  to  the  figure  of  the  earth.  From 
this,  as  Laplace(^**)  has  significantly  observed, 
might  an  astronomer,  "  without  leaving  his  ob- 
servatory, by  a  comparison  of  the  lunar  theory 
with  positive  observations,  determine,  not  only 
the  figure  and  magnitude  of  the  earth,  but  far- 
ther, its  distance  from  the  sun  and  from  the 
moon  ;  results  which  have  only  been  obtained 
by  long  and  toilsome  journeys  undertaken  to 
the  remotest  countries  of  either  hemisphere.'^ 
The  oblateness  which  has  been  deduced  from 
the  inequalities  of  the  moon  has  this  advantage, 
possessed  neither  by  single  measuremcBts  ol 
degrees  nor  pendulum  observations,  that  it  is  a 
MEAN  applicable  to  the  whole  planet.  Contrast- 
ed with  the  velocity  of  rotation,  it  informs  us, 
moreover,  of  the  increase  of  density  of  the 
earth's  strata  from  the  surface  towards  the 
centre ;  an  increase  which  the  comparison  of 
the  relation  of  the  axes  of  Jupiter  and  Saturn 
with  their  periods  of  rotation  also  reveals  in 
both  of  these  great  planets.  In  this  way  does 
knowledge  of  mere  external  configuration  fead 
to  conclusions  in  regard  to  the  internal  consti- 
tution of  the  heavenly  bodies. 

The  northern  and  southern  hemispheres  ap- 
pear to  have  nearly  like  curvatures  under  equal 
parallels  of  latitude(^°*) ;  but  pendulum  experi- 
ments, and  measurements  of  degrees  of  the 
meridian,  give  such  different  results  in  refer- 


INTERNAL  TEMPERATURE  OF  THE  EARTH. 


ftt 


ence  to  particular  portions  of  the  surface,  that 
nothing  like  a  regular  figure  can  be  inferred 
which  would  accord  with  the  whole  of  the  re- 
sults hitherto  obtained  in  these  ways.  The 
true  figure  of  the'  earth  stands  in  the  same  re- 
lation to  a  regular  figure.  "  as  the  uneven  sur- 
face of  ruffled  stands  to  the  even  surface  of 
unruffled  water." 

After  the  earth  has  been  measured,  it  must 
be  WEIGHED.  Pendulum  vibrations  and  the 
plumb-line  have  alike  served  to  determine  the 
nean  density  of  the  earth — whether  the  rela- 
tive density  was  investigated  by  a  combina- 
lion  of  astronomical  and  geodetical  operations, 
through  the  deflection  of  a  plumb-line  from  the 
perpendicular  in  the  vicinity  of  a  mountain,  or 
by  contrasting  the  length  of  the  pendulum  beat- 
ing seconds  on  a  plain  and  on  the  summit  of  a 
neighbouring  height,  or,  finally,  by  the  applica- 
tion of  the  torsion-balance,  which  may  be  re- 
garded as  a  delicate  horizontally  swinging  pen- 
dulum. Of  these  three  methods(^"),  the  last 
is  the  safest,  inasmuch  as  it  is  independent  of 
the  difficult  determination  of  the  density  of  the 
minerals  composing  the  spherical  segment  of  a 
mountain  in  the  neighbourhood  of  which  the 
observations  are  made.  The  latest  research- 
es, which  are  those  of  Reich,  give  5-44  as  the 
mean  density  of  the  whole  earth ;  that  is  to 
say,  the  earth  is  nearly  5^^  times  more  dense 
than  pure  water.  But  as  the  mineral  species 
which  constitute  the  dry  land  have  a  mean 
density  of  no  more  than  about  2-7,  and  the  dry 
land  and  the  ocean  together  a  density  of  but 
1-6,  it  follows  from  this  assumption  how  much 
the  elliptical  unequally  oblated  strata  of  the  in- 
terior must  increase  in  density  through  pres- 
sure, or  through  heterogeneousness  of  material 
towards  the  centre.  And  here  we  see,  again, 
with  what  propriety  the  pendulum,  both  that 
which  swings  perpendicularly  and  that  which 
swings  horizontally,  has  been  designated  a  ge- 
ognostical  instrument. 

But  the  conclusions  to  which  the  use  of  such 
an  instrument  leads,  have  induced  distinguish- 
ed natural  philosophers  to  take  entirely  oppo- 
site views  of  the  constitution  of  the  earth's  in- 
terior. It  has  been  calculated  at  what  depth 
liquid,  and  even  aeriform  bodies,  would  come 
to  surpass  platinum,  and  even  iridium,  in  den- 
sity, through  the  proper  pressure  of  their  own 
superimposed  strata  ;  and  in  order  to  bring  the 
oblateness  of  the  earth's  spheroid,  known  with- 
in a  very  small  quantity,  into  harmony  with 
the  assumption  of  a  single  and  infinitely  com- 
pressible substance,  the  acute  Leslie  has  gone 
so  far  as  to  have  described  the  nucleus  of  the 
earth  as  a  hollow  sphere,  filled  with  '*  impon- 
derable matter  of  enormous  repulsive  powers." 
These  daring  and  arbitrary  conjectures  have 
given  rise  to  still  more  fantastical  dreams  in 
non-scientific  circles.  The  hollow  sphere  has, 
by  degrees,  been  peopled  with  plants  and  ani- 
mals, and  furnished,  moreover,  with  a  couple 
of  small  subterranean  planets — Pluto  and  Pros- 
erpine, which  there  dispense  their  gentle  light. 
An  unvarying  temperature  reigns  in  this  inter- 
nal space,  and  the  air,  self-luminous  by  com- 
pression, might  well  make  the  presence  of  the 
subterraneous  planets,  Pluto  and  Proserpine, 
unnecessary.    Near  the  north-pole,  under  the 


82d  parallel  of  latitude,  where  the  aurora  bo- 
realis  streams  up  into  the  sky,  there  is  an  en- 
ormous opening,  through  which  it  were  easy  to 
descend  into  the  hollow  sphere.  To  such  a 
subterranean  expedition  the  late  Sir  Humphry 
Davy  and  I  were  repeatedly  and  publicly  invi- 
ted by  Captain  Symmes.  So  strongly  is  the 
morbid  disposition  of  man  inclined,  unencum- 
bered with  the  contradictory  testimony  of  well- 
established  facts  or  generally  admitted  natural 
laws,  to  fill  unseen  space  with  marvellous 
forms  !  But  the  celebrated  Halley  himself,  at 
the  end  of  the  17th  century,  had  hollowed  out 
the  earth  in  the  course  of  his  magnetical  spec- 
ulations :  a  subterraneous  freely  rotating  nu- 
cleus, by  its  varying  position,  occasions  the 
diurnal  and  annual  variations  of  the  magnetical 
declination !  What  was  a  mere  lively  fiction 
with  the  clever  Holberg,  has,  in  our  days,  with 
tedious  solemnity,  been  attempted  to  be  decked 
out  in  a  scientific  garb. 

The  figure  of  the  earth,  and  the  degree  of 
solidity  or  density  which  it  possesses,  stand  in 
intimate  connection  with  the  forces  which  an- 
imate our  globe,  in  so  far,  namely,  as  these 
forces  are  not  excited  or  awakened  from  with- 
out by  our  planetary  position  opposite  to  a  self- 
luminous  central  body.  The  oblateness,  a  con- 
sequence of  the  operation  of  the  centrifugal 
force  upon  a  rotating  mass,  reveals  the  pristine 
or  former  state  of  fluidity  of  our  planet.  On 
the  setting  or  solidification  of  this  fluid,  which 
we  are  accustomed  to  conjecture  as  existing  in 
the  shape  of  a  vaporiform  matter,  originally 
heated  to  a  very  high  temperature,  an  enormous 
amount  of  latent  caloric  became  free.  If  the 
process  of  consolidation  began  in  the  way 
Fourier  will  have  it,  by  radiation  from  the  sur- 
face into  celestial  space,  the  parts  of  the  earth 
which  are  situated  towards  the  centre  must 
still  be  hot  and  molten.  While,  after  long  ra- 
diation of  the  heat  of  the  central  parts  towards 
the  surface,  a  state  of  stability  in  the  tempera- 
ture of  the  earth  is  finally  attained,  it  is  at  the 
same  time  assumed  that,  with  an  increase  in 
depth,  there  will  also  be  a  regular  progressive 
increase  of  temperature.  The  temperature  of 
the  water  which  flows  from  bores  of  great 
depth  into  the  bowels  of  the  earth  (Artesian 
wells),  immediate  experiments  on  the  temper- 
ature of  the  rocks  in  mines,  above  all,  however, 
the  volcanic  activity  of  the  earth,  in  other  words, 
the  discharge  of  molten  mineral  streams  through 
fissures  in  the  surface,  bear  testimony  in  the 
most  incontestable  manner  to  this  increase  of 
temperature  in  the  upper  strata  of  the  earth  at 
considerable  depths.  From  conclusions  which, 
it  is  true,  are  only  founded  on  analogy,  it  is 
more  than  probable  that  the  temperature  goes 
on  increasing  in  a  still  greater  degree  towards 
the  centre. 

The  conclusions  which  have  been  presented 
to  us  by  an  ingenious,  and,  for  this  class  of  in- 
quiries, singularly  perfect  analytical  calculus, 
on  the  motion  of  heat  in  homogeneous  metallic 
spheroids(^"),  can  only  be  applied,  with  many 
precautions,  to  the  actual  constitution  of  our 
planet,  in  consequence  of  our  ignorance  of  the 
matter  of  which  the  earth  is  composed,  of  the 
various  capacities  for  heat  and  powers  of  con- 
duction inherent  in  the  superimposed  masses, 


54 


MEAN  TEMPERATURE  OF  THE  EARTH. 


and  of  the  chemical  transformations  which 
solid  and  fluid  bodies  undergo  under  enormous 
pressures.  Most  difficult  of  all,  for  our  powers 
of  comprehension,  is  the  conception  of  the 
boundary  line  betwixt  the  fluid  masses  of  the 
interior  and  the  concrete  mineral  species  of  the 
outer  crust  of  the  earth,  of  the  gradual  increase 
of  solidity  in  the  strata,  and  the  state  of  tena- 
cious semi-fluidity  of  earthy  matters,  to  which 
the  known  laws  of  hydraulics  can  only  apply 
under  considerable  modifications.  The  sun  and 
moon,  which  keep  the  ocean  in  a  state  of  alter- 
nate ebb  and  flow,  act  in  all  likelihood  even 
down  to  these  depths.  Beneath  a  vault  of  al- 
ready consolidated  mineral  strata,  periodical 
rises  and  falls  of  a  molten  mass  may,  indeed, 
be  readily  enough  conceived  as  taking  place, 
and  occasioning  inequalities  in  the  pressure  ex- 
erted against  the  vault.  The  amount  and  the 
influence  of  such  oscillations  can,  however,  be 
but  small ;  and  if  the  relative  position  of  the 
attracting  heavenly  bodies  must  here  also  pro- 
duce spring-tides,  it  is  still  certain  that  the  con- 
cussions of  the  earth's  surface  which  take  place, 
are  not  to  be  ascribed  to  these,  but  to  other 
more  powerful  internal  forces.  There  are 
groups  of  phenomena,  the  existence  of  which 
it  is  still  useful  to  adduce  in  illustration  of  the 
universality  of  the  attractive  influences  of  the 
sun  and  moon  upon  the  external  and  internal 
life  of  the  globe,  however  little  we  may  feel 
ourselves  in  a  condition  to  determine  numeri- 
cally their  amount. 

From  experiments  on  Artesian  wells,  which 
agree  pretty  closely,  the  temperature  of  the 
upper  crust  of  the  earth  appears,  on  an  aver- 
age, to  increase  1°  of  the  centigrade  thermom- 
eter for  each  92  Paris  feet  in  perpendicular 
depth.  Did  this  increase  go  on  in  arithmetical 
progression,  then,  as  I  have  already  had  occa- 
sion to  observe(^<'8),  would  a  granitic  stratum 
at  the  depth  of  Sy^^  geographical  miles  (from 
four  to  five  times  the  depth  of  the  highest  peak 
in  the  Himalaya  range)  be  in  a  molten  state. 

In  the  body  of  the  earth  there  are  three  kinds 
of  motion  of  heat  to  be  distinguished  :  the  first 
is  periodical,  and,  according  to  the  position  of 
the  sun  and  the  season  of  the  year,  alters  the 
temperature  of  the  earth's  strata  according  as 
the  heat  penetrates  from  above  downwards,  or 
as  it  passes  in  the  same  way  from  below  up- 
wards. The  second  kind  of  motion  is  likewise 
an  effect  of  the  sun,  and  is  of  extraordinary 
slowness :  part  of  the  heat  which  has  pene- 
trated the  equatorial  regions  is  propagated 
along  the  interior  of  the  crust  of  the  earth 
towards  the  poles,  and  there  escapes  into  the 
atmosphere  and  distant  space.  The  third  kind 
of  motion  is  the  slowest  of  all :  it  consists  in 
the  secular  cooling  of  the  body  of  the  earth,  in 
the  dissipation  of  the  small  amount  of  the  prim- 
itive heat  of  the  planet  which  at  the  present 
time  is  still  given  off  from  its  surface.  This 
loss  which  the  central  heat  suffers  was  very 
considerable  at  the  epochs  of  the  oldest  revolu- 
tions of  the  globe  ;  since  the  commencement 
of  the  historical  period,  however,  it  is  scarcely 
mensurable  by  our  instruments.  The  surface 
of  the  earth,  from  the  foregoing  view,  is  inter- 
mediate between  the  red  heat  of  the  interior 
strata,  and  the  temperature  of  space,  which  is 
probably  below  the  congealing  point  of  mercury. 


The  periodical  variations  of  temperature 
which  the  altitude  of  the  sun  and  the  meteoro^ 
logical  processes  of  the  atmosphere  occasion, 
are  propagated  in  the  interior  of  the  earth,  but 
only  to  very  small  depths.  This  slow  conduc- 
tion of  heat  by  the  ground,  however,  lessens 
the  loss  of  warmth  in  the  winter,  and  is  favour- 
able to  deeply-rooted  trees.  Points  which  lie 
at  different  depths  in  a  vertical  line  come  to 
the  maximum  and  minimum  of  the  communi- 
cated temperature  in  very  different  times.  The 
more  distant  they  are  from  the  surface,  the 
smaller  are  the  differences  of  these  extremes. 
On  the  continent  of  Europe,  between  the  paral- 
lels of  48°  and  52°,  the  stratum  of  invariable 
temperature  occurs  at  from  55  to  GO  feet  deep ; 
even  at  half  this  depth  the  oscillations  of  the 
thermometer,  in  consequence  of  the  influence 
of  the  seasons,  scarcely  amount  to  half  a  de- 
gree. In  tropical  climates,  on  the  contrary, 
the  stratum  of  invariable  temperature  is  met 
with  at  no  more  than  a  foot  below  the  surface  ; 
and  this  fact  has  been  used  by  Boussingault, 
in  an  able  manner,  as  a  convenient  and,  in  his 
opinion,  accurate  way  of  determining  the  mean 
temperature  of  the  air  of  a  place(^°').  This 
mean  temperature  of  the  air  at  a  determinate 
point,  or  in  a  group  of  points  of  the  surface  ly- 
ing near  to  one  another,  is,  in  a  certain  meas- 
ure, the  fundamental  element  of  the  climatic 
relations,  and  also  of  the  relations  in  reference 
to  civilization  of  a  country  ;  but  the  mean  tem- 
perature of  the  whole  surface  is  very  different 
from  that  of  the  earth  itself  The  oft-repeated 
questions,  whether,  in  the  course  of  centuries, 
this  has  suffered  any  considerable  change? 
whether  the  climate  of  a  country  has  become 
deteriorated  1  whether  the  winters  have  not 
become  milder,  and  the  summers  in  the  same 
proportion  colder  1  can  only  be  decided  by  the 
thermometer  ;  and  the  discovery  of  this  instru- 
ment scarcely  dates  three  half-centuries  back ; 
its  rational  application  no  more  than  about  120 
years.  The  nature  and  novelty  of  the  means, 
therefore,  prescribe  very  narrow  bounds  to  in- 
quiries into  the  temperature  of  the  air.  It  is 
quite  otherwise  with  the  solution  of  the  groat 
problem  of  the  internal  heat  of  the  whole  globe. 
In  the  same  way  as  from  the  unaltered  rate  of 
a  pendulum  we  can  conclude  on  the  unchanged 
preservation  of  its  temperature,  so  does  the 
unaltered  velocity  of  rotation  of  the  earth  on 
its  axis  inform  us  of  the  degree  of  stability  of 
its  mean  temperature.  This  perception  of  the 
relations  between  the  length  of  the  day  and  the 
earth's  temperature,  is  one  of  the  most  brilliant 
applications  of  a  long  knowledge  of  the  heaven- 
ly motions  to  the  thermal  condition  of  our  plan- 
et. The  velocity  of  rotation  of  the  earth,  to 
wit,  depends  on  its  volume :  precisely  as  the 
axis  of  rotation  of  the  mass  that  was  cooling 
gradually  by  radiation  would  become  shorter, 
so  through  diminution  in  temperature  must  the 
velocity  of  rotation  be  increased,  and  the  length 
of  the  day  be  abridged.  Now  by  a  comparison 
of  the  secular  inequalities  of  the  moon's  mo- 
tions with  the  eclipses  that  have  been  observed 
in  the  more  ancient  times,  it  appears  that  since 
the  age  of  Hipparchus.  for  full  2000  years  there- 
fore, the  length  of  the  day  has  not  varied  by  the 
one-hundredth  part  of  a  second.  From  this, 
again,  and,  within  the  utmost  limits  of  the  de- 


MAGNETISM. 


55 


CTease(*"),  the  mean  temperature  of  the  body 
of  the  earth  is  discovered  not  to  have  altered, 
in  the  course  of  2000  years,  by  the  yiy^th  part 
of  a  thermometrical  degree. 

This  invariableness  of  form  farther  implies 
great  invariability  in  the  distribution  of  density 
in  the  interior  of  the  earth.  The  translatory 
movements  effected  by  the  erfiptions  of  our 
present  volcanoes,  the  outbursts  of  ferruginous 
lavas,  and  the  filling  up  of  empty  chasms  and 
hollows  vrith  dense  masses  of  rock,  are  there- 
fore to  be  regarded  as  mere  superficial  phe- 
nomena, as  peculiarities  of  parts  of  the  earth's 
crust,  which,  in  point  of  magnitude,  when  con- 
trasted with  the  semidiameter  of  the  earth,  are 
utterly  insignificant. 

The  internal  heat  of  the  planet,  in  its  course 
and  distribution,  I  have  described  almost  ex- 
clusively from  the  results  and  beautiful  experi- 
ments of  Fourier.  Poisson,  however,  doubts 
the  uninterrupted  increase  of  the  terrestrial 
heat  from  the  surface  to  the  centre.  He  be- 
lieves that  all  the  heat  has  penetrated  from 
without  inwards,  and  that  the  temperature  of 
the  interior  of  the  earth  depends  on  the  very 
high  or  very  low  temperature  of  the  universal 
space  through  which  the  solar  system  has  mo- 
ved. This  hypothesis,  devised  by  one  of  the 
most  profound  mathematicians  of  the  age,  has 
satisfied  himself  only ;  it  has  met  with  little 
countenance  from  other  natural  philosophers 
and  geologists. 

But  whatever  be  the  cause  of  the  internal 
temperature  of  our  planet,  and  of  its  limited  or 
unlimited  increase  in  the  deeper  strata,  it  still 
leads  in  this  Essay  to  present  a  general  picture 
of  nature,  through  the  intimate  connection  of 
all  the  primary  phenomena  of  matter,  and 
through  the  common  bond  which  surrounds 
the  molecular  forces,  into  the  obscure  domain 
of  Magnetism.  Changes  of  temperature  elicit 
magnetical  and  electrical  currents.  Terres- 
trial magnetism,  whose  principal  character  in 
the  threefold  manifestation  of  its  force  is  an 
uninterrupted  periodic  changeableness,  is  ascri- 
bed either  to  the  unequally  heated  mass  of  the 
earth  itself('"),  or  to  those  galvanic  currents 
which  we  consider  as  electricity  in  motion,  as 
electricity  in  a  circuit  returning  into  itself("^). 
The  mysterious  march  of  the  magnetic  needle 
is  equally  influenced  by  the  course  of  the  sun, 
and  change  of  place  upon  the  earth's  surface. 
The  hour  of  the  day  can  be  told  between  the 
tropics  by  the  motion  of  the  needle,  as  well  as 
by  the  oscillations  of  the  mercury  in  the  barom- 
eter. It  is  suddenly,  though  only  passingly, 
affected  by  the  remote  Aurora,  by  the  glow  of 
heaven,  which  emanates  in  colours  at  one  of 
the  poles.  When  the  tranquil  hourly  motion 
of  the  needle  is  disturbed  by  a  magnetical 
storm,  the  perturbation  frequently  proclaims 
itself  over  hundreds  and  thousands  of  miles,  in 
the  strictest  sense  of  the  word  simultaneously, 
or  it  is  propagated  gradually,  in  brief  intervals 
of  time,  in  every  direction  over  the  surface  of 
the  earthO").  In  the  first  case  the  simultane- 
ousness  of  the  storm  might  serve,  like  the 
e'dipses  of  Jupiter's  satellites,  fire  signals,  and 
well-observed  shooting  stars,  within  certain 
limits,  for  the  determination  of  geographical 
longit^es.    It  is  seen  with  amazement,  that 


the  tremblings  of  two  small  magnetic  needles, 
were   they  suspended  deep  in  subterraneous  ' 

space,  measure  the  distance  that  intervenes 
between  them  ;  that  they  tell  us  how  far  Kasan 
lies  east  from  Gottingen,  or  from*  the  banks  of 
the  river  Seine.  There  are  regions  of  the  earth 
where  the  seaman,  enveloped  for  days  in  fog, 
without  sight  of  the  sun  or  stars,  without  all 
other  means  of  ascertaining  the  time,  can  still 
accurately  determine  the  hour  by  the  variation 
of  the  dip  of  the  needle,  and  know  whether  he 
be  to  the  north  or  south  of  the  port  towards 
which  he  would  steer  his  courseC^*). 

If  the  sudden  perturbation  of  the  needle  in 
its  hourly  course  makes  known  the  occurrence 
of  a  magnetic  storm,  the  seat  of  the  perturbing 
cause — whether  it  be  to  seek  in  the  crust  of 
the  earth  itself,  or  in  the  upper  regions  of  the 
air — remains,  to  our  extreme  regret,  as  yet  un- 
determined. If  we  regard  the  earth  as  an  ac- 
tual magnet,  then  are  we  compelled,  according 
to  the  decision  of  the  deep-thinking  founder  of 
a  general  theory  of  terrestrial  magnetism, 
Frederick  Gauss,  to  admit  that  every  eighth  of 
a  cubic  metre,  or  y^ths  of  a  cubic  foot  of  the 
earth,  possesses,  on  an  average,  at  least  as 
much  magnetism  as  a  one-pound  magnetic 
bar("*).  If  iron  and  nickel,  and  probably  co- 
balt also  —  not  chrome,  as  was  long  sup- 
posed("*),  be  the  only  substances  which  be- 
come permanently  magnetic,  and  retain  polar- 
ity by  a  certain  coercive  force,  the  phenomena 
of  Arago's  rotative  magnetism,  and  Faraday's 
induced  currents,  assure  us,  on, the  other  hand, 
that  probably  all  terrestrial  substances  may 
passingly  comport  themselves  magnetically. 
From  the  experiments  of  the  first  of  the  great 
natural  philosophers  just  mentioned,  water, 
ice(^*^),  glass,  and  charcoal,  affect  the  oscilla- 
tions of  the  needle  precisely  as  quicksilver  does 
in  the  rotatory  experiments.  Almost  all  sub- 
stances show  themselves  in  a  certain  degree 
magnetic  when  they  are  conductors  ;  that  is  to 
say,  wiien  they  are  traversed  by  a  current  of 
electricity. 

How  ancient  the  knowledge  of  the  attractive 
power  of  natural  magnetic  iron  appears  to  have 
been  among  the  western  nations  (and  this  his- 
torically well-authenticated  fact  is  remarkable 
enough),  the  knowledge  of  the  polarity  or  di- 
rective force  of  the  magnetic  needle,  and  its 
connection  with  terrestrial  magpetism,  was, 
nevertheless,  confined  to  the  extreme  east  of 
Asia,  to  the  Chinese.  A  thousand  years  and 
more  before  the  commencement  of  our  era,  in 
the  dark  epoch  of  Codru  and  the  return  of  the 
Heraclidae  to  the  Peloponnesus,  the  Chinese 
had  already  magnetic  cars,  upon  which  the 
moveable  arm  of  a  human  figure  pointed  inva- 
riably to  the  south,  as  a  means  of  finding  the 
way  through  the  boundless  grassy  plains  of 
Tartary ;  in  the  third  century,  indeed,  of  the 
Christian  era,  at  least  seven  hundred  years, 
therefore,  before  the  introduction  of  the  ship's 
compass  upon  European  seas,  Chinese  crafl 
were  sailing  the  Indian  ocean  under  the  gui- 
dance   of  MAGNETIC    SOUTHERN    INDICATI0N("'). 

I  have  shown  in  another  work("'),  what  ad- 
vantages this  method  of  determining  topograph- 
ical position,  this  early  knowledge  and  applica- 
tion of  the  magnetic  needle,  wholly  unknown 
in  the  west,  gave  the  Chinese  geographers  over 


56 


MAGNETISM. 


those  of  Ancient  Greece  and  Rome,  to  whom, 
for  example,  the  true  course  of  the  Apennines 
and  Pyrenees  was  never  known. 

The  magnetic  force  of  our  planet  reveals  it- 
self on  its  surface  in  three  classes  of  phenom- 
ena, one  of  which  shows  the  variable  intensity 
of  the  force,  the  two  others  indicate  the  varia- 
ble direction  in  the  inclination  or  dip,  and  in  the 
horizontal  departure,  or  declination,  from  the  ter- 
restrial meridian  of  the  place,  the  aggregate  out- 
ward effect  of  which  may  be  graphically  exhibit- 
ed by  means  of  three  systems  of  lines,  one  isody- 
namical,  another  isoclinial,  a  third  isogonial ; 
or  lines  of  equal  force,  of  equal  dip,  and  of 
equal  variation.  The  distance  and  relative  po- 
sition of  these  ever-moved,  oscillatingly-pro- 
gressive  curves,  do  not  always  remain  the 
same.  The  total  variation  or  declination  of 
the  magnetic  needle  has  not,  however,  chan- 
ged appreciably,  or  at  all  in  certain  parts  of 
the  earthc^'"),  in  the  Western  Antilles  and  in 
Spitzbergen,  for  example,  in  the  course  of  a 
whole  century.  Even  so,  the  isogonial  curves, 
when,  in  the  course  of  their  secular  movement, 
they  have  passed  from  the  surface  of  the  sea 
to  a  continent  or  island  of  considerable  magni- 
tude, are  seen  to  linger  long  upon  it,  and  then 
they  curve  off  again  in  their  farther  progress. 

These  gradual  transformations  which  accom- 
pany the  translation,  and  in  the  course  of  time 
extend  the  empire  of  the  Eastern  and  Western 
variations  so  unequally,  render  it  difficult,  in 
the  graphic  representations  that  belong  to  dif- 
ferent centuries,  to  discover  the  transitions  and 
analogies  of  the  forms.  Every  branch  of  a 
curve  has  its  own  history ;  but  this  history, 
among  the  Western  nations,  nowhere  mounts 
higher  than  to.the  remarkable  epoch,  the  13th  of 
September,  1493,  when  the  rediscoverer  of  the 
New  World  recognized  a  line  of  no  variation, 
three  degrees  west  from  the  meridian  of  Flores, 
one  of  the  Azores('''^).  The  whole  of  Europe, 
a  small  portion  of  Russia  alone  excepted,  has, 
at  the  present  time,  western  variation  ;  whilst, 
at  the  end  of  the  17th  century,  first  in  London 
(1657),  and  then  in  Paris  (1669),  with  a  differ- 
ence of  twelve  years,  consequently,  despite  the 
short  distance  between  them,  the  needle  point- 
ed directly  to  the  north  pole.  In  East  Russia, 
to  the  east  of  the  mouth  of  the  Wolga,  of  Sar- 
atow,  Nijni-Novogorod  and  Archangel,  the 
Eastern  variation  presses  in  upon  us  from 
Asia.  Two  excellent  observers,  Hansteen  and 
Ad.  Erman,  have  given  us  intelligence  of  the 
remarkable  double  curvature  of  the  variation- 
lines  in  the  wide-spread  realms  of  Northern 
Asia ;  convex  towards  the  pole  betwixt  Ob- 
dorsk  and  Obi  and  Turuchansk,  concave  be- 
twixt lake  Baikal  and  the  bay  of  Ochotsk.  In 
this  last  part  of  the  earth,  in  the  north-east  of 
Asia,  betwixt  the  Werchojansk  mountains, 
Jakutsk  and  Northern  Corea,  the  isogonial  lines 
form  a  remarkable  system  enclosed  within  it- 
self. This  ovoidal  formation("')  is  more  reg- 
ularly repeated,  and  on  a  larger  scale,  in  the 
South  Sea,  nearly  in  the  meridian  of  Pitcairn 
island  and  the  Marquesas  group,  betwixt  the 
parallels  of  20°  N.  and  45°  S.  latitude.  One 
might  feel  disposed  to  regard  so  singular  a 
configuration  of  self-included,  almost  concen- 
tric lines  of  variation,  as  the  effect  of  a  pecu- 
liar local  constitution  of  the  body  of  the  earth  ; 


but  should  these  apparently  isolated  systems 
move  on  in  the  course  of  centuries,  then,  as 
in  all  grand  natural  forces,  must  some  more 
general  cause  of  the  phenomenon  be  presumed. 

The  hourly  changes  in  the  variation,  depend- 
ent on  the  true  time,  and  apparently  determin- 
ed by  the  sun  so  long  as  it  is  above  the  horizon 
of  a  place,  decrease  in  their  angular  amount 
with  the  magnetic  latitude.  Near  the  Equator, 
in  Rawak  Island,  for  example,  they  are  scarce- 
ly more  than  from  3  to  4  minutes,  whilst  in  the 
middle  of  Europe  they  amount  to  from  13  to  14 
minutes.  Now,  as  the  north  end  of  the  needle, 
in  the  whole  of  the  northern  hemisphere,  trav- 
els, on  an  average,  between  half-past  8  a.m.  and 
half-past  1  P.M.  from  east  to  west;  and  in  the 
southern  hemisphere  the  same  north  end  trav- 
erses from  west  to  east  during  the  same  period 
of  time,  it  has  been  recently,  and  with  reason, 
remarked("'),  that  there  must  be  a  region  of 
the  earth  situated,  probably,  between  the  ter 
restrial  and  the  magnetic  equator,  in  which  no 
horary  changes  of  the  variation  will  be  observ- 
ed. But  this  fourth  curve,  that  of  no-move- 
ment, or  rather  of  no  change  in  horary  varia 
tion,  has  not  yet  been  discovered. 

As  the  points  of  the  earth's  surface  where 
the  horizontal  force  disappears,  are  called  mag 
netic  poles,  and  a  greater  degree  of  importance 
has  been  attached  to  these  points  than  belonga 
to  them  of  right(^'^*),  in  the  same  way  is  that 
curve  called  the  magnetic  equator  upon  which 
the  dip  of  the  needle  is  nothing.  The  positioD 
of  this  line,  and  its  secular  variations  of  form, 
have  been  made  objects  of  particular  investiga 
tion  in  recent  times.  From  the  admirable  work 
of  Duperrey(^*^),  who,  between  the  years  1822 
and  1825,  crossed  the  magnetic  equator  six 
times,  it  appears  that  the  two  points  in  which 
the  line  of  no  dip  cuts  the  terrestrial  equator, 
and  so  passes  from  one  hemisphere  into  anoth- 
er, are  so  unequally  divided,  that,  in  the  year 
1825,  the  node  by  the  island  of  St.  Thomas,  on 
the  west  coast  of  Africa,  lay  in  a  direct  line 
188^°  from  the  node  in  the  South  Sea  by  the 
little  Gilbert's  Island  (nearly  in  the  meridian 
of  the  Viti  group),  in  the  Southern  Pacific.  In 
the  beginning  of  the  present  century,  at  an  el- 
evation of  11,200  feet  above  the  level  of  the 
sea,  in  70°  V  S.  lat.  and  48°  40'  W.  long.,  I 
was  enabled  astronomically  to  determine  the 
point  at  which  the  Andes  betwixt  Quito  and 
Lima,  in  the  interior  of  the  New  Continent, 
are  crossed  by  the  magnetic  equator.  From 
this  point,  proceeding  westward,  it  lingers  in 
the  southern  hemisphere,  through  almost  the 
whole  of  the  South  Sea,  slowly  approaching  the 
terrestrial  equator.  It  first  crosses  over  into 
the  northern  hemisphere  shortly  before  it  reach- 
es the  Indian  Archipelago ;  it  then  just  touch- 
es the  south  point  of  Asia,  and  enters  the  Afri- 
can continent  westward  from  Socotora,  close 
to  the  straits  of  Babelmandel,  where  it  is  at  its 
greatest  elongation  from  the  terrestrial  equa- 
tor. Traversing  the  unknown  regions  of  cen- 
tral Africa  in  a  south-western  direction,  the 
magnetic  equator  returns,  in  the  gulph  of 
Guinea,  into  the  southern  tropic,  and  in  its 
course  across  the  Atlantic  separates  so  far 
from  the  terrestrial  equator,  that  it  meets  the 
coast  of  Brazil  at  Os  Ilheos,  to  the  north  of 
Porto  Seguro,  in  15°  S.  latitude.    Fron^ence 


MAGNETISM. 


67 


to  the  lofty  plains  of  the  Cordilleras,  betwixt 
the  silver  mines  of  Micuipampa  and  the  old 
seat  of  the  Incas,  Caxamarca,  where  I  had  an 
opportunity  of  observing  th(?  inclination,  it  trav- 
erses the  whole  of  South  America,  which,  in 
these  southern  latitudes,  like  the  interior  of 
Africa,  remains  a  magnetic  terra  incognita  up 
to  the  present  time. 

Late  observations  collected  by  Colonel  Sa- 
bine(^2*),  inform  us  that  the  node  of  the  Island 
of  St.  Thomas  has  travelled  four  degrees,  from 
east  to  west,  between  1825  and  1837.  It  would 
be  of  the  highest  importance  to  know  whether 
the  opposite  node  of  Gilbert's  Island,  in  the 
South  Pacific,  had  not  travelled  as  far  west- 
ward, towards  the  meridian  of  the  Carolinas. 
The  general  survey  now  given  must  suffice  to 
connect  the  different  systems  of  not  perfectly 
parallel  isoclinal  lines  with  the  great  phenome- 
non of  equilibrium  which  manifests  itself  in  the 
magnetic  equator.  It  is  no  small  advantage 
for  the  establishment  of  the  laws  of  terrestrial 
magnetism,  that  the  magnetic  equator,  whose 
fluctuating  alterations  of  form,  and  whose  nodal 
motion  in  the  midst  of  the  various  magnetic  lat- 
itudes, exert  an  influence("')  upon  the  dip  of 
the  needle  in  the  remotest  countries  of  the 
world,  is,  with  the  exception  of  one-fifth,  whol- 
ly oceanic  ;  it  is  therefore,  through  the  remark- 
able relations  betwixt  the  sea  and  the  land,  by 
so  much  the  more  accessible,  as  we  are  now 
in  possession  of  a  means  of  determining  both 
variation  and  dip,  with  great  accuracy,  on  ship- 
board, whilst  the  vessel  is  holding  her  course. 

We  have  now  portrayed  the  distribution  of 
magnetism  upon  the  surface  of  our  planet,  ac- 
cording to  the  two  forms  of  variation  and  dip. 
The  third  form,  that  of  intensity  of  the  force, 
still  remains,  and  this  is  graphically  expressed 
by  isodynamic  curves  (lines  of  equal  intensity). 
The  investigation  and  measurement  of  this 
force,  in  its  terrestrial  relations,  by  the  oscilla- 
tions of  a  vertical  or  horizontal  needle,  have 
only  excited  general  and  lively  interest  since 
the  beginning  of  the  nineteenth  century.  The 
measurement  of  the  horizontal  force  has  been 
made  capable  of  a  degree  of  accuracy,  particu- 
larly by  the  application  of  delicate  optical  and 
chronometrical  instruments,  which  far  exceeds 
that  of  all  the  other  magnetical  determinations. 
If,  with  reference  to  the  immediate  application 
to  navigation  and  steering,  the  isogonal  lines 
be  the  more  important,  the  isodynamic,  espe- 
cially those  that  indicate  the  horizontal  force, 
present  themselves,  according  to  the  most  re- 
cent views,  as  those  which  promise  the  richest 
harvest  for  the  theory  of  terrestrial  juagnet- 
ism(i28).  One  of  the  earliest  facts  discovered 
by  observation,  was  this  :  that  the  intensity  of 
the  sum  of  the  force  increases  from  the  equa- 
tor towards  the  pole(i*9). 

For  a  knowledge  of  the  measure  of  this  in- 
crease, and  the  establishment  of  all  numerical 
relations  of  the  law  of  intensity,  embracing  the 
whole  earth,  we  are  especially  indebted  to  the 
ceaseless  activity  of  Colonel  Sabine,  who,  ever 
since  the  year  1819,  after  he  had  made  obser- 
vations on  the  same  needle  oscillating  at  the 
American  north  pole,  in  Greenland,  in  Spitz- 
bergen,  on  the  coast  of  Guinea,  and  in  the  Bra- 
zils, has  been  incessantly  engaged  m  collecting 
and  alranging  whatever  may  serve  to  illustrate 


the  direction  of  the  isodynamic  lines.  I  have 
myself  given  the  first  plan  of  an  isodynamical 
system,  divided  into  zones,  for  a  small  part  of 
South  America.  These  isodynamic  lines  are 
not  parallel  to  the  lines  of  equal  dip ;  the  in- 
tensity of  the  force  is  not,  as  was  at  first  be- 
lieved, weakest  at  the  magnetic  equator ;  it  is 
not  once  equal  at  any  part  of  the  same.  If 
Erman's  observations  in  the  southern  portion 
of  the  Atlantic,  where  a  zone  of  declining  in- 
tensity runs  from  Angola,  over  the  island  of 
St.  Helena,  to  the  coast  of  Brazil  (0706),  be 
compared  with  the  very  latest  observations  of 
that  distinguished  navigator  Sir  James  Clark 
Ross,  it  is  found  that  the  force  upon  the  surface 
of  our  planet  increases  nearly  in  the  ratio  of  one 
to  three  towards  the  magnetic  south  pole,  and 
where  Victoria  Land  stretches  away  from  Cape 
Crozier  towards  Mount  Erebus,  that  volcano 
which  rises  from  everlasting  ice  to  the  height 
of  11,600  feet  above  the  level  of  the  sea('3'>).  If 
the  intensity  in  the  vicinity  of  the  magnetic 
south  pole  be  expressed  by  2052  ( — the  inten- 
sity which  I  found  on  the  magnetic  equator  in 
North  Peru  is  still  assumed  as  unity,  or  1  000), 
Sabine  found  it,  in  Melville  Island,  24°  27'  N. 
lat.,  near  the  magnetic  north  pole,  only  1-624  ; 
whilst,  in  the  United  States,  near  New- York — 
nearly  under  the  same  parallel  of  latitude  as 
Naples,  consequently — it  was  1  -803. 

Through  the  brilliant  discoveries  of  Oersted, 
Arago,  and  Faraday,  the  electrical  charge  of 
the  atmosphere  has  been  brought  to  approxi- 
mate more  closely  to  the  magnetical  charge  of 
the  earth.  If  Oersted  found  that  electricity  in- 
duced magnetism  in  the  vicinity  of  the  body 
which  was  conducting  it,  so,  on  the  other  hand, 
it  was  shown  in  Faraday's  experiments  that 
free  magnetism  gave  rise  to  electricity.  Mag- 
netism is  one  of  the  numerous  forms  in  which 
electricity  manifests  itself  The  ancient  sus- 
picion of  the  identity  of  electrical  and  magnet- 
ical attraction  has  been  demonstrated  in  the 
present  age.  "  If  electrum"  (amber),  says 
Pliny  (^^^),  in  the  sense  of  the  Ionic  natural 
philosophy  of  Thales,  "  becomes  inspired  by 
friction  and  warmth,  it  attracts  bark  and  dried 
leaves,  exactly  like  the  magnetic  iron  stone." 
The  same  words  occur  in  the  literature  of  a 
people  inhabiting  the  easternmost  parts  of  Asia, 
in  the  discourse,  laudatory  of  the  magnet,  of 
the  Chinese  natural  philosopher,  Kuopho(^32) 
It  was  not  without  surprise  that  I  myself  ob- 
served, among  the  children  at  play  on  the  woody 
banks  of  the  Orinoco,  the  offspring  of  native 
tribes  in  the  lowest  grade  of  civilization,  that 
the  excitement  of  electricity  by  friction  was 
known.  The  boys  rubbed  the  dry,  flat,  and 
shining  seeds  of  a  creeping  leguminous  plant 
(probably  a  negretia),  until  they  attracted  fibres 
of  cotton  wool  and  chips  of  the  bamboo.  1  his 
amusement  of  these  coppery  children  is  calcu- 
lated to  leave  a  deep  and  solemn  impression  be- 
hind it.  What  a  chasm  lies  between  the  elec- 
trical play  of  these  savages,  and  the  discovery 
of  the  lightnmg  conductor,  of  the  chemically 
decompounding  pile,  of  the  light-evolving  mag- 
netical apparatus !  In  such  gulphs,  millenni- 
ums in  the  history  of  the  intellectual  progress 
of  mankind  lie  buried ! 

The  ceaseless  change,  the  fluctuating  move- 
ments which  are  observed  in  all  magnetical 


NORTHERN  LIGHTS. 


phenomena — those  of  the  dip,  variation,  and  in- 
tensity, according  to  the  hour  of  the  day  and 
even  of  the  night,  according  to  the  season  and 
the  lapse  of  whole  years,  permit  us  to  suspect 
the  existence  of  very  dissimilar  partial  sys- 
tems of  electrical  currents  in  the  crust  of  the 
earth.  Are  these  currents,  as  in  Seebeck's  ex- 
periments, thermo-magnetical,  and  immediate- 
ly excited  by  unequal  distribution  of  heat  1  Or 
shall  we  not  rather  regard  them  as  induced  by 
the  position  of  the  sun,  and  through  the  influ- 
ence of  his  heat  1(^2')  Has  the  rotation  of  our 
planet  and  the  accident  of  the  diflTerent  veloci- 
ties impressed  upon  the  several  zones,  accord- 
ing to  their  distance  from  the  equator,  any  in- 
fluence upon  the  distribution  of  magnetism  ■! 
Shall  the  seat  of  the  currents,  in  other  words, 
of  the  electricity  in  motion,  be  sought  for  in 
the  atmosphere,  in  the  interplanetary  spaces, 
or  in  the  polarity  of  the  sun  and  moon  1  Gali- 
leo, in  his  celebrated  Dialogo,  is  disposed  to 
ascribe  the  parallel  direction  of  the  earth's  axis 
to  a  magnetic  point  of  attraction  in  space. 

When  the  interior  of  the  earth  is  regarded 
as  molten  and  subjected  to  an  enormous  pres- 
sure, as  raised  to  a  degree  of  temperature  such 
as  we  have  no  means  of  estimating,  then  must 
the  idea  of  a  magnetical  nucleus  of  the  earth 
be  abandoned.  All  magnetism  is  certainly  lost 
at  a  white  heat("*) ;  it  is  still  manifested  when 
iron  is  raised  to  a  dull  red ;  and  however  dif- 
ferent the  modifications  undergone  by  the  mole- 
cular condition,  and  the  coercive  force  of  mat- 
ter dependent  on  it,  may  be  in  experiments, 
there  still  remains  a  considerable  thickness  of 
the  crust  of  the  earth  which  might  be  assumed 
as  the  seat  of  magnetic  currents.  In  what  re- 
gards the  old  explanation  of  the  horary  varia- 
tions of  the  deflection,  by  the  progressive  heat- 
ing of  the  earth  in  the  apparent  course  of  the 
sun  from  east  to  west,  it  must  be  owned  that 
we  are  here  limited  to  the  very  outermost  sur- 
face ;  inasmuch  as  the  thermometers  now  sunk 
in  the  ground  in  so  many  places,  and  so  care- 
fully observed,  show  us  how  slowly  the  sun's 
heat  penetrates  even  to  the  moderate  depth  of 
a  few  feet.  And  then  the  thermal  state  of  the 
surface  of  the  ocean,  covering  two-thirds  of 
the  globe,  is  little  favourable  to  such  an  expla- 
nation, when  the  question  is  one  of  immediate 
mean  influence,  not  of  induction  from  the  ae- 
rial and  vaporous  covering  of  our  planet. 

To  all  questions  as  to  the  ultimate  physical 
cause  of  phenomena  so  complicated,  there  is 
no  satisfactory  answer  to  be  given  in  the  pres- 
ent state  of  our  knowledge.  It  is  only  in  ref- 
erence to  the  three-fold  manifestations  of  the 
earth-force,  to  that  which  meets  us  as  mensu- 
rable relations  of  Space  and  of  Time,  as  the 
Normal  or  conformable  to  laws  in  the  Variable, 
that  brilliant  advances  have  lately  been  made, 
through  the  determination  of  numerical  mean 
values.  Since  the  year  1828,  from  Toronto,  in 
Upper  Canada,  to  the  Cape  of  Good  Hope  and 
Van  Dieman's  Land,  from  Paris  to  Pekin,  the 
earth  has  been  covered  with  magnetical  observ- 
atories(^"),  in  which  uninterrupted  and  simul- 
taneous observations  are  made  of  every  reg- 
ular and  irregular  excitement  of  the  earth-force. 
A  decrease  of  the  magnetic  intensity  amount- 
ing to  the  y^^^^th  part  is  measured ;  at  cer- 
tain epochs,  observations  are  noted  every  2i 


minutes  through  an  entire  period  of  24  hours. 
An  illustrious  English  astronomer  and  natural 
philosopher(*3')  has  calculated  that  the  mass  of 
observations  accumulated  in  the  course  of  three 
years,  which  remain  for  discussion,  amounts  to 
1,958,000  !  Never  has  there  been  so  grand,  so 
delightful  an  eflTort  made  to  get  at  the  root  of 
the  Quantitative  in  the  laws  of  a  natural  phe- 
nomenon. We  may  therefore  be  permitted  to 
entertain  a  well-grounded  hope,  that  these 
laws,  compared  with  those  which  prevail  in 
the  atmosphere,  and  still  more  distant  spaces, 
will  gradually  bring  us  nearer  and  nearer  to  the 
Genetical  in  magnetic  phenomena.  Until  now 
we  can  only  boast  that  a  greater  number  of 
ways  which  might  possibly  lead  to  information 
have  been  opened  up.  In  the  physical  doctrine 
of  terrestrial  magnetism,  which  must  not  be 
confounded  with  the  purely  mathematical  one, 
as  in  the  doctrine  of  the  meteorological  pro- 
cesses of  the  atmosphere,  some  completely 
satisfy  themselves  by  conveniently  denying  as 
realities  all  the  phenomena  which  cannot  be 
explained  in  conformity  with  their  views. 

Terrestrial  magnetism,  the  electro-dynamic 
forces  which  have  been  calculated  by  the  able 
Ampere(^^^),  stands  at  the  same  time  in  inti- 
mate relationship  with  the  Earth-  or  North- 
ern-Lights [Aurora  borealis],  as  with  the  in- 
ternal and  external  temperature  of  our  globe, 
whose  magnetic  poles  must  be  regarded  as  poles 
of  cold("8).  If  Haliey('3'),  some  128  years  ago, 
gave  it  out  as  a  mere  bold  conjecture  that  the 
northern  light  was  a  magnetic  phenomenon, 
Faraday's  brilliant  discovery  of  the  evolution  of 
light  through  magnetic  power  has  raised  that 
conjecture  to  the  rank  of  an  empirical  certainty. 
There  are  heralds  or  harbingers  of  the  northern 
lights.  In  the  course  of  the  day  on  which  the 
lights  are  to  appear,  irregular  horary  movements 
of  the  magnetic  needle  usually  indicate  an  in- 
terruption of  equilibrium  in  the  distribution  of 
the  terrestrial  magnetism.  When  this  disturb- 
ance has  attained  a  great  intensity,  the  equilib- 
rium of  the  distribution  is  restored  by  a  dis- 
charge, accompanied  with  an  evolution  of  light. 
"  The  northern  light  itself  is  not,  therefore,  to 
be  regarded  as  an  external  cause  of  the  disturb- 
ance, but  rather  as  a  terrestrial  activity  raised 
to  the  pitch  of  a  luminous  phenomenon,  one  of 
the  sides  of  which  is  the  light,  the  other  the 
oscillations  of  the  needle"(**<').  The  splendid 
phenomenon  of  coloured  northern  lights  is  the 
act  of  discharge,  the  conclusion  of  a  magnetic 
storm  ;  in  the  same  way  as,  in  the  electrical 
storm,  an  evolution  of  light — lightning — indi- 
cates the  restoration  of  the  disturbed  equilib- 
rium in  the  distribution  of  electricity.  The 
electrical  storm  is  usually  limited  to  a  small 
space,  beyond  which  the  state  of  the  electricity 
remains  unchanged.  The  magnetic  storm,  on 
the  contrary,  reveals  its  influence  on  the  march 
of  the  needle  over  large  portions  of  continents, 
as  Arago  first  observed,  and  far  from  the  place 
where  the  development  of  light  is  visible.  It  is 
not  improbable  that,  as  in  the  case  of  heavily 
charged  and  threatening  clouds,  and  of  frequent 
transitions  of  the  atmospheric  electricity  into 
opposite  states,  it  does  not  always  come  to  dis- 
charges by  lightning,  so  also  may  magnetic 
storms  produce  great  disturbances  in  th^orary 


NORTHERN  LIGHTS. 


motions  of  the  needle  over  extensive  circles, 
without  there  being  any  necessity  for  explo- 
sions, for  luminous  effusions  from  the  pole  to 
the  equator,  or  from  one  pole  to  another,  in  or- 
der to  restore  the  equiUbrium. 

He  who  w^ould  have  all  the  particulars  of  the 
phenomenon  embraced  in  one  picture,  should 
have  the  origin  and  course  of  a  complete  ap- 
pearance of  the  northern  lights  set  before  him. 
Deep  on  the  horizon,  nearly  m  the  situation 
where  it  is  intersected  by  the  magnetic  merid- 
ian, the  heaven,  up  to  this  moment  clear, 
grows  black.  There  is  a  kind  of  hazy  bank  or 
screen  produced,  which  rises  gradually,  and  at- 
tains to  an  altitude  of  from  8  to  10  degrees. 
The  colour  of  the  dusky  segment  passes  over 
into  brown  or  violet.  Stars  are  visible  in  it, 
but  they  are  seen  as  in  a  portion  of  the  sky  ob- 
scured with  dense  smoke.  A  broad  bright 
luminous  arc  or  seam,  first  white,  then  yellow, 
bounds  the  dusky  segment ;  but  as  the  brilliant 
bow  arises  later  than  the  snjoky-grey  segment, 
it  is  impossible,  according  to  Argelander('"),  to 
ascribe  the  latter  to  the  effect  of  mere  contrast 
with  the  bright  luminous  border.  The  highest 
point  of  the  luminous  arc,  when  it  has  been 
carefully  measured("*),  has  usually  been  found 
to  be  not  exactly  in  the  magnetic  meridian,  but 
to  vary  between  5  and  18  degrees  from  it,  to- 
wards the  side  on  which  the  magnetic  declina- 
tion of  the  place  of  observation  lies.  In  high 
northern  latitudes,  very  near  the  north  pole,  the 
smoky-looking  spherical  segment  appears  less 
dark ;  sometimes  it  is  even  entirely  absent.  In 
the  situation,  too,  where  the  horizontal  force  is 
least,  the  middle  of  the  luminous  arc  is  seen  to 
depart  farthest  from  the  magnetic  meridian. 

The  luminous  bow,  in  constant  motion,  flick- 
ering and  changing  its  form  incessantly,  some- 
times remains  visible  for  hours  before  anything 
like  rays  and  pencils  of  rays  shoot  from  it,  and 
rise  to  the  zenith.  The  more  intense  the  dis- 
charges of  the  northern  lights,  the  more  vividly 
do  the  colours  play  from  violet  and  bluish-white, 
through  every  shade  and  gradation,  to  green 
and  purplish-red.  In  our  ordinary  electricity 
produced  by  friction,  in  the  same  way,  the  spark 
first  becomes  coloured  when  the  tension  is  high, 
and  the  explosion  is  violent.  The  magnetic 
fiery  columns  shoot  up  at  one  time  singly  from 
the  luminous  arch,  even  mingled  with  black 
rays,  like  thick  smoke  ;  at  another,  many  col- 
umns arise  simultaneously  from  several  and  op- 
posite points  of  the  horizon,  and  unite  in  a 
flickering  sea  of  flame,  to  the  splendour  of  which 
no  description  can  do  justice,  and  whose  lumi- 
nous waves  assume  another  and  a  different 
shape  at  every  instant.  The  intensity  of  the 
northern  light  is  at  times  so  great,  that  Lowe- 
norn  perceived  its  oscillations,  in  bright  sun- 
shine, on  the  29th  of  January,  1786.  The  mo- 
tion increases  the  brilliancy  of  the  phenomenon. 
Around  the  point  of  the  vault  of  heaven  which 
corresponds  with  the  direction  of  the  dipping 
needle,  the  rays  at  length  collect  together,  and 
form  the  corona  or  crown  of  the  northern  lights. 
This  surrounds  the  summit,  as  it  were,  of  a 
vast  canopy,  the  dome  of  heaven,  with  the  mild 
radiance  of  its  streaming  but  not  flickering  rays. 
It  is  only  in  rare  instances  that  the  phenomenon 
proceeds  the  length  of  forming  the  corona  com- 
pletely.   With  its  appearance,  however,  the 


whole  is  at  an  end.  The  rays  now  become 
rarer,  shorter,  less  intensely  coloured.  The 
crown  and  the  luminous  arches  break  up.  By 
and  by  nothing  but  broad,  motionless,  and  al- 
most ashy-grey,  pale  gleaming  fleecy  masses, 
appear  irregularly  dispersed  over  the  whole 
vault  of  heaven  ;  these  vanish,  in  their  turn, 
and  before  the  last  trace  of  the  murky  fuligin- 
ous segment,  which  still  shows  itself  deeply  on 
the  horizon,  has  disappeared.  Of  the  whole 
briUiant  spectacle,  nothing  at  length  remains 
but  a  white  delicate  cloud,  feathered  at  the 
edges,  or  broken  up,  as  a  cirro-cumulus,  into 
small  rounded  masses  or  heaps,  at  equal  dis- 
tances. 

This  connection  of  the  polar  light  with  the 
most  delicate  cirrus-clouds,  deserves  to  be  par- 
ticularly mentioned ;  inasmuch  as  it  shows  us 
the  electro-magnetic  evolution  of  light  as  part 
of  a  meteorological  process  The  terrestrial 
magnetism  here  manifests  itself  in  its  effects 
upon  the  atmosphere,  in  a  condensation  of  the 
watery  vapour  which  it  holds  dissolved.  The 
observations,  made  in  Iceland  by  Thienemann, 
who  regards  the  cirro-cumulus,  or  divided  fleecy 
cloud,  as  the  substrate  of  the  northern  lights, 
have  been  confirmed  in  later  times  by  Franklin 
and  Richardson,  near  the  North  American  mag 
netic  pole,  and  by  Admiral  Wrangel,  on  the  Si- 
berian coasts  of  the  icy  sea.  All  observed 
'*  that  the  northern  lights  sent  forth  the  most 
brilliant  fays  when  masses  of  cirro-stratus 
floated  in  the  upper  regions  of  the  atmosphere  ; 
and  when  these  were  so  thin,  that  their  pres- 
ence was  only  known  by  the  formation  of  a 
halo  about  the  moon."  These  light  clouds  oc- 
casionally arranged  themselves,  by  day,  in  the 
same  manner  as  the  rays  of  the  Aurora,  and 
had  the  same  effect  as  these  in  disturbing  the 
magnetic  needle.  After  a  grand  nocturnal  dis- 
play of  the  northern  lights,  the  same  streaks  of 
clouds  that  had  been  luminous  over  night,  were 
discovered  in  the  morning  arranged  in  the  same 
manner^").  The  apparently  converging  polar 
zones  of  clouds  (streaks  of  clouds,  in  the  direc- 
tion of  the  magnetic  meridian),  which  constant- 
ly attracted  my  attention  in  the  course  of  my 
travels  on  the  lofty  platforms  of  Mexico,  as  well 
as  in  Northern  Asia,  belong  apparently  to  the 
same  group  of  diurnal  phenomenaC^**). 

Southern  hghts  have  been  frequently  seen  in 
England  by  that  able  and  diligent  observer,  Dal- 
ton  ;  northern  lights  in  the  southern  hemisphere, 
as  low  as  45°  of  latitude  (Jan.  14,  1831).  In 
instances  that  are  not  very  rare,  the  magnetic 
equilibrium  is  disturbed  at  both  poles  simultane- 
ously. I  have  distinctly  stated  that  northern 
polar  lights  are  seen  within  the  tropics,  even  as 
far  south  as  Mexico  and  Peru.  It  is  necessary 
to  distinguish,  however,  between  the  sphere  of 
a  simultaneous  apparition  of  the  phenomenon, 
and  the  zone  of  the  earth  in  which  the  phe- 
nomenon is  displayed  almost  every  night  of  the 
year.  As  each  observer  sees  his  own  rainbow, 
so  also,  doubtless,  does  he  see  his  own  polar 
light.  A  great  portion  of  the  earth  engenders 
the  radiating  Light-phenomenon  at  the  same 
time.  Many  nights  can  be  mentioned  in  which 
it  was  observed  simultaneously  in  England,  in 
Pennsylvania,  in  Rome,  and  in  Pekin.  When 
it  is  maintained  that  the  northern  lights  decline 
with  the  decrease  of  latitude,  this  must  be  un- 


NORTHERN  LIGHTS. 


derstood  as  referring  to  magnetic  latitude,  meas- 
ured from  the  magnetic  pole.  In  Iceland,  Green- 
land, and  Newfoundland,  on  the  banks  of  the 
Slave  lake,  and  at  Fort  Enterprise  (in  North 
Canada),  the  Aurora  is  lighted  up,  at  certain 
seasons,  almost  every  night,  and  with  its  shift- 
ing, shivering  rays,  performs  its  **  merry  dance" 
through  the  sky,  as  the  natives  of  the  Shetland 
Islands  term  it('**).  Whilst  in  Italy  the  north- 
ern light  is  a  great  rarity,  it  is  seen  with  ex- 
treme frequency  in  the  latitude  of  Philadelphia 
(39°  57'  N.  L.),  in  consequence  of  the  southern 
position  of  the  American  magnetic  pole.  But  in 
the  districts  of  the  new  continent,  and  also  of 
the  shores  of  Siberia,  which  are  remarkable  for 
the  frequency  of  the  phenomenon,  there  occur 
what  may  be  called  especial  regions  of  the 
northern  lights — longitudinal  zones  in  which 
they  are  peculiarly  splendid(^".)  Local  influ- 
ences are,  consequently,  not  to  be  overlooked. 
Wrangel  observed  their  brilliancy  decline  as  he 
left  the  shores  of  the  icy  sea,  about  Nijne-Ko- 
lymsk,  behind  him.  The  experience  of  the 
Northern  Polar  Expedition  seems  to  indicate 
that  the  evolution  of  light  is  not  greater  in  the 
immediate  vicinity  of  the  magnetic  pole  than  it 
is  at  some  distance  from  this  spot. 

What  we  know  of  the  altitude  of  the  northern 
light  is  based  on  measurements,  which,  by  reason 
of  the  incessant  oscillations  of  the  luminous 
rays,  and  the  consequent  uncertainty  of  the 
parallactic  angle,  cannot  be  greatly  depended  on. 
The  conclusions  come  to  (not  to  speak  of  older 
estimates)  vary  between  several  miles  and  three 
or  four  thousand  feet("^).  It  is  not  improbable 
that  the  northern  light  is  at  very  different  dis- 
tances at  different  times.  The  latest  observers 
are  disposed  to  connect  the  phenomenon,  not 
with  the  outer  limits  of  the  atmosphere,  but 
with  the  region  of  the  clouds  itself;  they  even 
believe  that  the  northern  streamers  may  be 
moved  by  winds  and  currents  of  air,  if  the 
luminous  phenomenon,  by  which  alone  the  ex- 
istence of  electro-magnetic  emanations  becomes 
obvious  to  us,  be  actually  connected  with  mate- 
rial collections  of  vesicular  vapour,  or,  to  speak 
more  correctly,  penetrates  these  collections, 
darting  over  from  one  vesicle  to  another.  Cap- 
tain Franklin  saw  a  streaming  Aurora  on  Bear 
lake,  which  he  believed  illuminated  the  under 
side  of  the  stratum  of  cloud  ;  whilst  Kendal, 
who  had  the  watch  through  the  whole  of  the 
night,  and  never  lost  the  heavens  for  a  minute 
from  his  sight,  at  the  distance  of  but  4^  geo- 
graphical miles,  observed  no  luminous  phe- 
nomenon whatsoever.  The  statement,  repeat- 
ed several  times  of  late,  to  the  effect  that 
streamers  of  the  northern  light  have  been  ob- 
served close  to  the  ground,  and  between  the 
observer  and  a  neighbouring  height,  is  one  of 
those  points,  which,  like  lightning  and  the  fall 
of  fire-balls,  is  exposed  to  the  manifold  dangers 
of  optical  deception. 

Whether  or  not  the  magnetic  storm,  of  which 
we  have  just  quoted  a  remarkable  example 
of  local  circumscription  within  very  narrow 
bounds,  have  the  noise,  besides  the  light,  in 
common  with  the  electrical  storm,  is  now  ren- 
dered extremely  doubtful,  since  the  testimony 
of  the  Greenland  sledgers,  and  the  Siberian 
fox-hunters,  is  no  longer  taken  unconditionally. 
The  northern  lights  have  become  more  silent 


since  they  have  been  examined  more  carefully 
with  the  eye  and  the  ear.  Parry,  Franklin  and 
Richardson,  near  the  north  pole  ;  Thienemann, 
in  Iceland  ;  Gieseke,  in  Greenland  ;  Lottin  and 
Bravais,  at  the  North  Cape  ;  Wrangel  and  An- 
jou,  on  the  shores  of  the  icy  sea,  have,  alto- 
gether, looked  at  thousands  of  northern  lights, 
yet  never  heard  any  noises.  If  this  negative 
testimony  be  not  admitted  against  two  positive 
witnesses,  Hearne,  at  the  mouth  of  the  Copper- 
mine river,  and  Henderson,  in  Iceland,  it  must 
still  be  remembered  that  Hood  heard  the  same 
noises — as  of  musket  balls  shaken  rapidly  to- 
gether, and  slight  cracklings,  during  the  occur- 
rence of  the  northern  lights,  indeed,  but  also 
on  the  following  day,  when  there  was  no  Au- 
rora in  the  heavens  ;  and  then  it  must  not  be 
forgotten,  that  Wrangel  and  Gieseke  were  firm- 
ly convinced  that  the  noises  heard  were  owing 
to  contractions  of  the  ice  and  crust  of  snow, 
in  consequence  of  a  sudden  cooling  of  the  air. 
The  belief  in  a  crapkling  noise  did  not  take  its 
origin  among  the  people,  but  with  learned  trav- 
ellers, and  in  this  way :  the  flashing  of  elec- 
tricity in  attenuated  atmospheres  having  been 
known  from  an  early  period,  the  northern  light 
was  forthwith  declared  to  be  an  effect  of  at- 
mospheric electricity,  and  then  the  noises  were 
heard  that  ought  to  have  been  heard.  Recent 
experiments  with  the  most  delicate  electrome- 
ters, however,  contrary  to  all  expectation,  have 
hitherto  given  merely  negative  results  ;  the 
state  of  the  aerial  electricity  has  not  been  found 
altered  during  the  prevalence  of  the  most  brill- 
iant Auroras. 

All  the  three  manifestations  of  force  of  the 
terrestrial  magnetism  —  Declination,  Inclina- 
tion, and  Intensity,  on  the  contrary,  are  affect- 
ed at  once  by  the  northern  lights.  In  one  and 
the  same  night,  and  from  hour  to  hour,  the  Au- 
rora affects  the  same  end  of  the  needle  differ- 
ently, now  attracting  it,  now  repelling  it.  The 
assertion  that  the  facts  collected  by  Parry  at 
Melville  Island,  near  the  magnetic  pole,  lead  to 
the  conclusion  that  the  northern  lights  do  not 
disturb  the  needle,  but  rather  have  a  "  calming 
effect"  upon  it,  is  completely  contradicted  by  a 
more  careful  perusal  of  Parry's  own  journa](^*^), 
by  the  beautiful  observations  of  Richardson, 
Hood,  and  Franklin  in  North  Canada,  and  more 
lately  still,  by  Bravais  and  Lotten  in  Lapland. 
The  process  in  the  northern  lights  is,  as  we 
have  above  observed,  the  act  of  restoration  of 
an  equilibrium  disturbed.  The  effect  upon  the 
needle  varies  according  to  the  measure  of  force 
in  the  explosion.  It  was  only  unobservable  at 
the  nocturnal  winter  station  at  Bosekop,*  when 
the  luminous  phenomenon  showed  itself  very 
feebly  and  deep  on  the  horizon.  The  upshoot- 
ing  radiate  cyhnders  of  the  northern  light  have 
been  aptly  compared  to  the  flame  which,  in  the 
closed  circuit  of  the  Voltaic  pile,  arises  be- 
tween two  charcoal  points  at  a  distance  from 
one  another,  or,  according  to  Fizeau,  between 
a  silver  and  a  charcoal  point,  and  to  that  which 
is  drawn  or  thrown  off  from  the  magnet.  This 
analogy  at  all  events  renders  superfluous  the 
assumption  of  those  metallic  vapours  in  the 
atmosphere  which  some  natural  philosophers 


*  [Vide  Kaemtz's  Complete  Course  of  Meteorolog^y,  by 
C.  V.  Walker,  (Plates,  8vo.  Lond.  1845),  for  a  full  accouut 
of  the  Aurora.— Tb.] 


EARTHQUAKES. 


01 


have  imagined  as  the  substrate  of  the  northern 
lights. 

If  the  luminous  phenomenon  which  we  as- 
cribe to  a  galvanic  current,  t.  e,  a  motion  of 
electricity  in  a  circuit  returning  into  itself,  be 
designated  by  the  indefinite  name  of  the  North- 
ern light,  or  the  Polar  light,  nothing  more  is 
thereby  implied  than  the  local  direction  in 
which  the  beginning  of  a  certain  luminous  phe- 
nomenon is  most  generally,  but  by  no  means 
invariably,  seen.  What  gives  this  phenomenon 
its  greatest  importance  is  the  fact  which  it  re- 
veals, viz.  that  the  Earth  is  luminous  ;  that 
our  planet,  beside  the  light  which  it  receives 
from  the  central  body,  the  sun,  shows  itself 
capable  of  a  proper  luminous  act  or  process. 
The  intensity  of  the  Earth-light,  or  rather  the 
degree  of  luminosity  which  it  diffuses,  exceeds 
by  a  little,  in  the  case  of  the  brightest  coloured 
rays  that  shoot  up  to  the  zenith,  the  light  of 
the  moon  in  her  first  quarter.  Occasionally,  as 
on  the  7th  of  January,  1831,  a  printed  page  can 
he  read  without  straining  the  sight.  This  light- 
process  of  the  earth,  which  the  Polar  regions 
exhibit  almost  incessantly,  leads  us  by  analogy 
to  the  remarkable  phenomenon  which  the  planet 
Venus  presents.  The  portion  of  this  planet 
which  is  not  illuminated  by  the  sun,  glows  oc- 
casionally with  a  proper  phosphorescent  gleam. 
It  is  not  improbable  that  the  Moon,  Jupiter,  and 
Comets,  besides  the  reflected  sun-light  recog- 
nizable by  the  polariscope,  also  emit  light  pro- 
duced by  themselves.  Without  insisting  on  the 
problematical  but  very  common  phenomenon 
of  sheet-lightning,  in  which  the  whole  of  a  deep 
massy  cloud  is  flickeringly  illuminatecf  for  sev- 
eral minutes  at  a  time,  we  find  other  examples 
of  terrestrial  evolutions  of  light.  To  this  head 
belong  the  celebrated  dry-fogs  of  1783  and  1831, 
which  were  luminous  by  night ;  the  steady  lu- 
minottsness  of  large  clouds,  perfectly  free  from 
all  flickering,  observed  by  Rosier  and  Beccaria ; 
and  even  the  pale,  diffused  light,  as  Arago  has 
well  observed^'**),  which  serves  to  guide  us  in 
the  open  air,  in  thickly  clouded  autumn  and 
wintry  nights,  when  there  is  neither  moon 
nor  star  in  the  firmament,  nor  snow  upon  the 
ground.  As  in  the  phenomenon  of  the  Polar 
lights  occurring  in  high  northern  latitudes,  in 
other  words,  in  electro^magnetic  storms,  floods 
of  flickering  and  often  parti-coloured  light 
stream  through  the  air,  so,  in  the  hotter  zones 
of  the  earth,  between  the  tropics,  are  there 
many  thousand  square  miles  of  ocean  which 
are  similarly  light-engendering.  Here,  how- 
ever, the  magic  of  the  light  belongs  to  the  or- 
ganic forces  of  nature.  Light-foaming  flashes 
the  bursting  wave,  the  wide  level  glows  with 
lustrous  sparks,  and  every  spark  is  the  vital 
motion  of  an  invisible  animal  world.  So  mani- 
fold is  the  source  of  terrestrial  light.  And  shall 
we  conceive  it  latent,  not  yet  set  free  in  va- 
pours, as  a  means  of  explaining  Moser's  pic- 
tures— a  discovery  in  which  reality  still  pre- 
sents itself  to  us  as  a  vision  shrouded  in  mys- 
tery? 

As  the  internal  heat  of  our  planet  is  connect- 
ed on  one  hand  with  the  excitement  of  electro- 
magnetic currents  and  the  light-producing  pro- 
cess of  the  earth  (a  consequence  of  the  burst- 
ing of  a  magnetic  storm),  so  on  the  other  hand 


does  it  also  manifest  itself  as  a  principal  source 
of  geognostic  phenomena.  These  we  shall  con- 
sider in  their  connection,  and  in  their  transition 
from  a  merely  dynamic  concussion,  and  from 
the  upheaving  of  continents  and  mountain  mass- 
es, to  the  production  and  effusion  of  gases  and 
liquids,  of  boiling  mud,  and  of  red  hot  and  molt- 
en earths,  which  harden  into  crystalline  rocks. 
It  is  no  trifling  advance  in  the  newer  geognosy 
(the  mineralogical  portion  of  the  physics  of  the 
globe),  that  it  has  firmly  founded  the  concate- 
nation of  phenomena  here  indicated.  The 
views  of  modern  geognosy  lead  off  from  mere 
hypothesis,  which  trifles  or  plays  with  its  sub- 
ject, and  seeks  to  explain,  severally  and  apart, 
every  manifestation  of  force  of  the  old  globe  ; 
they  shew  the  connection  of  the  various  matters 
ejected  with  what  appertains  only  to  change  in 
reference  to  space — concussion,  elevation,  de- 
pression ;  they  arrange  side  by  side  groups  of 
phenomena  which  at  first  sight  present  them- 
selves as  extremely  heterogeneous — thermal 
springs,  effusions  of  carbonic  acid  gas,  escapes 
of  sulphureous  vapours,  harmless  eruptions  of 
mud,  and  the  awful  devastations  of  burning 
mountains.  In  a  grand  picture  of  nature  all 
this  becomes  fused  in  the  single  conception  of 
the  reaction  of  the  interior  of  a  planet  upon  its 
crust  and  surface.  So  do  we  recognize  in  the 
depths  of  the  earth,  in  its  temperature  increas- 
ing with  the  distance  from  the  surface,  at  once 
the  germs  of  concussive  movements,  of  the 
gradual  elevation  of  entire  continents,  or  of 
mountain  chains  through  lengthened  chasms, 
of  volcanic  eruptions,  and  of  the  varied  produc 
tion  of  mineral  species  and  rocky  masses.  Buf 
it  is  not  inorganic  nature  alone  that  has  felt  the 
force  of  this  reaction  of  the  interior  upon  the 
exterior.  It  is  extremely  probable  that  in  tht- 
primitive  world  immense  discharges  of  carbonic 
acid  gas  mingled  with  the  atmosphere,  excited 
the  faculty  possessed  by  vegetables  of  separa 
ting  carbon  from  the  air,  and  that  thus,  in  rev 
olutions  which  destroyed  extensive  forests,  in 
exhaustible  supplies  of  combustible  matter — 
lignites  and  coals  of  different  kinds — have  been 
buried  beneath  the  upper  strata  of  the  earth. 
The  destiny  of  man  we  even  recognize  as  m 
part  dependent  on  the  fashion  of  the  outer  crust 
of  the  globe,  on  the  partitioning  of  continents, 
on  the  direction  of  their  mountain  chains  anc' 
high  lands.  To  the  inquiring  spirit  is  it  givet 
to  mount  from  link  to  link  in  the  chain  of  phe- 
nomena, till  the  point  is  gained  at  which  in  thr» 
incipient  consolidation  of  our  planet,  in  the  firs*- 
transition  of  the  conglobated  matter  from  tb» 
vaporous  form,  the  internal  heat  of  the  earth, 
that  heat  which  does  not  belong  to  the  actioi 
of  the  sun,  was  developed. 

In  our  survey  of  the  causal  connection  ot 
geognostical  phenomena,  we  shall  begin  witit 
those  which,  in  their  principal  features,  are  dy- 
namical, which  consist  in  motion  and  a  changt 
in  space.  Earthquakes  of  every  kind  and  de* 
gree  are  distinguished  by  a  series  of  perpendic 
ular,  or  horizontal,  or  rotatory  vibrations  fo* 
lowing  each  other  in  rapid  succession.  In  thr 
course  of  the  considerable  number  of  earth 
quakes  which  I  have  felt  in  both  hemisphere* 
of  the  globe,  on  shore  and  at  sea,  the  two  firs< 
kinds  of  motion  have  appeared  to  me  very  fre- 
quently to  take  place  together.    The  explosive 


63 


EARTHQUAKES. 


movement  such  as  is  produced  by  the  firing  of 
a  mine — the  perpendicular  action,  from  below 
upwards — was  displayed  most  conspicuously  on 
the  occasion  when  the  town  of  Riobamba  was 
destroyed  (1797),  when  the  bodies  of  many  of 
the  inhabitants  were  thrown  upon  the  hill  of 
La  Culla,  which  is  several  hundred  feet  high, 
and  rises  on  the  other  side  of  the  Lican  rivulet. 
Tlie  propagation  of  the  motion  generally  takes 
place  in  a  linear  direction,  in  waves,  and  with 
a  velocity  of  from  five  to  seven  G.  geographical 
miles  in  a  minute.     Sometimes  it  is  in  circles, 
or  in  great  ellipses,  from  the  centre  of  which 
the  vibrations  are  propagated  with  decreasing 
force  towards  the  circumference.     There  are 
districts  which  belong  to  or  fall  within  two  mu- 
'   tually  intersecting  circles  of  concussion.     In 
North  Asia,  which  the  father  of  history(i*°), 
and,  after  him,  Simocatta(^*')  characterize  as 
"  the   Scythian    territories    free    from    earth- 
quakes," I  found  the  southern  part  of  the  Altai 
Mountains,  so  rich  in  mineral  treasures,  sub- 
ject to  the  influence  of  the  concussive  foci  both 
of  Lake  Baikal  and  the  volcanoes  of  Thian- 
Schan,  or  the  Celestial  Mountain^").     When 
the  circles  of  concussion  intersect  each  other — 
when,  for  instance,  a  lofty  plain  lies  between 
two   simultaneously  active  volcanoes  —  then 
may  several  systems  of  waves  exist  at  once, 
and  not  interfere  with  each  other,  just  as  in  the 
case  of  fluids.     Interference,  however,  can  be 
conceived  here,   as   in  mutually  intersecting 
waves  of  sound.     The  magnitude  of  the  trans- 
mitted wave  of  succussion  is  increased  at  the 
surface,  in  conformity  with  the  general  laws  of 
mechanics,  according  to  which,  when  motion 
is  communicated  in  elastic  bodies,  the  outer- 
most free-lying  stratum  tends  to  detach  itself 
from  the  others. 

The  waves  of  succussion  can  be  pretty  accu- 
rately measured  in  their  direction  and  total 
strength,  by  the  pendulum  and  the  sismomcter 
bowl,  but  in  no  way  investigated  in  the  intimate 
nature  of  their  alternations  and  periodical  intu- 
mescences. In  the  city  of  Quito,  which  stands 
at  the  foot  of  an  active  volcanic  mountain — the 
Rucu-Pichincha,  8,950  feet  above  the  level  of 
the  sea,  and  boasts  of  beautiful  cupolas,  lofty 
fanes,  and  massive  houses  several  stories  high, 
I  have  frequently  been  surprised  at  the  violence 
of  the  earthquakes  by  night,  which  neverthe- 
less very  rarely  occasion  rents  in  the  walls ; 
whilst  in  the  plains  of  Peru,  apparently  much 
weaker  oscillations  injure  lowly  houses  built  of 
cane.  Natives  who  have  stood  the  shocks  of 
many  hundred  earthquakes,  believe  that  the 
difference  of  effect  is  less  connected  with  the 
length  or  shortness  of  the  waves,  with  the 
slowness  or  rapidity  of  the  horizontal  oscilla- 
tion("^),  than  with  the  equality  of  the  motion 
in  opposite  directions.  Circular  or  rotatory 
concussions  are  the  rarest,  but  they  are  the 
most  dangerous  of  all.  Twistings  round  of 
walls  without  throwing  them  down  ;  planta- 
tions of  trees,  which  had  previously  stood  in 
parallel  rows,  deflected ;  the  direction  of  the 
ridges  of  fields  covered  with  various  kinds  of 
grain  altered,  were  observed  on  occasion  of  the 
great  earthquake  of  Riobamba,  in  the  province 
of  Quito  (February  4th,  1797),  as  well  as  of  those 
of  Calabria  (February  5th  and  March  28th,  1783). 
With  the  latter  phenomenon  of  rotation,  or  the 


transposition  of  fields  and  cultivated  plots  of 
ground,  of  which  one  has  occasionally  taken 
the  place  of  another,  there  is  connected  a  trans- 
latory  motion,  or  mutual  penetration  of  several 
strata.  When  taking  the  plan  of  the  ruined 
city  of  Riobamba,  I  was  shown  a  place  where 
the  whole  of  the  furniture  of  one  dwelling-house 
had  been  found  under  the  ruins  of  another.  The 
loose  earth  of  the  surface  had  run  in  streams 
like  a  fluid,  of  which  it  must  be  conceived  that 
it  was  first  directed  downwards,  then  horizon- 
tally, and  finally  upwards.  Disputes  about  the 
property,  in  those  instances  where  things  were 
carried  many  hundred  toises  from  their  original 
stances,  were  adjusted  by  the  Audiencia,  or 
Court  of  Justice. 

In  countries  where  earthquakes  are  compar- 
atively much  rarer,  in  the  south  of  Europe  for 
example,  a  very  general  belief,  grounded  upon 
an  imperfect  induction,  prevails(^**) ;  viz.  that 
calms,  oppressive  heats,  and  a  misty  state  of 
the  horizon,  are  always  preludes  to  an  earth- 
quake.    The  erroneousness  of  this  popular  be- 
lief is  not,  however,  shown  by  my  own  experi- 
ence only  ;   it  is  farther  gainsaid  by  the  obser- 
vations of  all  who  have  lived  long  in  countries 
where  earthquakes  are  frequent  and  violent,  as 
in  Cumana,  Quito,  Peru,  and  Chili.     I  have  ex- 
perienced earthquakes  when  the  air  was  clear 
and  a  fresh  east  wind  was  blowing,  as  well  as 
during  rain   and  thunder  storms.     Even  the 
regularity  in  the  horary  variations  in  the  decli- 
nation of  the  magnetic  needle,  and  in  the  press- 
ure of  the  air(*"),  remained  unaffected  within 
the  tropics  on  the  day  of  the  earthquakes.  The 
observarions  which  Adolphus  Erman  made  in 
the  temperate  zone  on  the  occasion  of  an  earth- 
quake at  Irkutsk,  near  lake  Baikal,  on  the  18th 
of  March,  1829,  agree  perfectly  with  my  expe- 
rience.    During  the  violent  earthquake  of  Cu- 
mana which  happened  on  the  4th  of  November, 
1799,  I  found  the  declination  of  the  needle  and 
the  magnetic  intensity  unaflfected ;  but  to  my 
astonishment  the  dip  was  diminished  by  48'('**). 
I  had  no  suspicion  of  any  error ;  yet  in  all  the 
other  earthquakes  which  I  have  experienced  in 
the  high  lands  of  Quito  and  in  Lima,  the  dip  of 
the  needle  remained  equally  unafTected  with 
the  other  elements  of  the  terrestrial  magnet- 
ism.    If  in  a  general  way  the  acts  that  proceed 
deep  in  the  interior  of  the  earth  are  annoimced 
beforehand  by  no  special  meteorological  phe- 
nomenon, by  no  peculiar  aspect  of  the  heavens, 
it  is  on  the  contrary  not  improbable,  as  we  shall 
see  immediately,  that  in  certain  very  violent 
earthquakes  the  atmosphere  has  sympathized 
or  partaken  in  some  measure,  and  that  these, 
therefore,  do  not  always  act  in  a  purely  dy- 
namical manner.     During  the  prolonged  trem- 
blings of  the  ground  in  the  Piedemontese  val- 
leys of  Pelis  and  Clusson,  extreme  changes  in 
the  electrical  tension  of  the  atmosphere  were 
observed,  whilst  the  heavens  were  free  from 
storm. 

The  strength  of  the  dull  noise  which  gener- 
ally accompanies  an  earthquake  does  not  by 
any  means  increase  in  the  same  measure  as  the 
strength  of  the  vibrations.  I  have  satisfactorily 
made  out  that  the  grand  concussion  in  the 
earthquake  of  Riobamba  (Feb.  4th,  1797),  one 
of  the  most  awful  catastrophes  in  the  physical 
history  of  our  earth,  was  accompanied  by  no 


EARTHQUAKES. 


noise  whatever.  The  great  noise  (cl  gran  ruido) 
which  was  heard  under  the  cities  of  Quito  and 
Ibarra,  but  not  nearer  the  centre  of  the  motion 
in  Tucunga  and  Hambato,  occurred  from  eigh- 
teen to  twenty  minutes  after  the  proper  catas- 
trophe. In  the  celebrated  earthquake  of  Lima 
and  Callao  (28th  Oct.  1746),  the  sound  was  first 
heard  Wke  a  subterraneous  peal  of  tliunder.in 
Truxillo  a  quarter  of  an  hour  later,  and  with- 
out any  trembling  of  the  ground.  In  like  man- 
ner, long  after  the  earthquake  of  New  Granada 
(Nov.  16th,  1827),  which  has  been  described  by 
Boussingault,  subterraneous  detonations  were 
heard  in  the  whole  of  the  valley  of  Cauca,  with 
great  regularity  at  intervals  of  thirty  seconds. 
The  nature  of  the  noises  heard  on  such  occa- 
sions is  very  various :  rolling,  rattling,  clank- 
ing like  chains,  occasionally  in  the  town  of 
Quito  like  thunder  close  at  hand  ;  or  it  is  clear 
and  ringing,  as  if  masses  of  obsidian  or  other 
vitrified  matters  were  struck  in  caverns  under- 
ground.-. As  solid  bodies  are  excellent  conduc- 
tors of  sound,  as  sound,  for  example,  is  trans- 
mitted with  ten  or  twelve  times  the  velocity  in 
burnt  clay  that  it  is  in  air,  the  subterraneous 
noise,  it  may  be  easily  imagined,  will  be  apt  to 
be  heard  at  great  distances  from  the  place 
where  it  is  occasioned.  In  Caraccas,  in  the 
grassy  plains  of  Calabozo,  and  on  the  banks  of 
the  Rio  Apure,  which  falls  into  the  Orinoco,  in 
the  whole  of  a  region  of  2300  square  miles  in 
superficial  extent,  there  was  heard  an  extraor- 
dinary thundering  noise,  without  any  shock  of 
an  earthquake,  on  the  30th  of  April,  1812,  at  the 
very  time  that  the  volcano  of  the  Island  of  St. 
Vincent,  lying  158  geographical  miles  off,  was 
pouring  an  immense  stream  of  lava  from  its 
crater.  This,  in  respect  of  distance,  was  as  if 
an  eruption  of  Vesuvius  were  to  be  heard  in  the 
north  of  France.  In  1744,  on  the  occasion  of 
the  great  eruption  of  Cotopaxi,  subterraneous 
cannonadings  were  heard  at  Honda  on  the  Rio 
Magdalena.  The  crater  of  Cotopaxi,  however, 
is  not  only  17,000  feet  above  the  level  of  Hon- 
da, but  the  two  points  are  separated  by  the  co- 
lossal mountain  masses  of  Quito,  Pasto,  and 
Popayan,  as  well  as  by  valleys  and  precipices 
innumerable,  besides  lying  109  geographical 
miles  apart.  The  sound  was  certainly  trans- 
mitted not  through  the  air,  but  through  the 
earth  from  a  great  depth.  In  the  violent  earth- 
quake of  New  Granada  (February,  1835),  sub- 
terraneous thunder  was  heard  at  the  same  time 
in  Popayan,  Bogota,  Santa  Martha,  and  Carac- 
cas (in  the  latter  for  a  period  of  seven  hours 
without  any  shock),  in  Haiti,  Jamaica,  and  round 
the  lake  of  Nicaragua  in  Mexico. 

These  sonorous  phenomena,  when  they  are 
accompanied  by  no  perceptible  shocks,  leave  a 
remarkably  deep  impression  even  v/ith  those 
who  have  long  dwelt  in  districts  subject  to  re- 
peated earthquakes.  All  seem  to  expect  with 
alarm  what  is  to  follow  the  subterraneous  rum- 
bling. The  most  remarkable  example  of  unin- 
terrupted subterraneous  noises,  without  any 
trace  of  earthquake,  and  comparable  with  no- 
thing else,  was  presented  by  the  phenomenon 
which  was  known  in  the  high  lands  of  Mexico 
under  the  name  of  the  subterraneous  beliowings 
and  thunderings  {bramidos  y  truenos  subtcrraneos) 
of  Guanaxuato("^).  This  celebrated  and  flour- 
ishing mining  town  lies  far  remote  from  any 


active  volcano.  The  noise  continued  from  mid- 
night of  the  9th  of  January,  1784,  for  more  than 
a  month.  I  have  been  able  to  give  a  particular 
account  of  it  from  the  report  of  many  witnesses, 
and  from  the  documents  of  the  municipality 
which  I  was  permitted  to  use.  It  was  (January 
13 — 16th)  ae  if  heavy  thunder-clouds  lay  under 
the  feet  of  the  inhabitants,  in  which  slowly  roll- 
ing thunder  alternated  with  sharper  claps.  The 
sound  drew  off  as  it  had  come  on  with  decreas- 
ing loudness.  It  was  confined  to  a  limited 
space  ;  at  the  distance  of  a  few  miles  off,  in  a 
district  abounding  in  basalt,  it  was  not  heard 
at  all.  Almost  all  the  inhabitants  fled  the  town 
in  alarm,  although  great  piles  of  silver  bars 
were  contained  in  it ;  the  more  courageous  be- 
coming accustomed  to  the  subterraneous  noise, 
by  and  by  returned  and  disputed  possession 
with  the  bands  of  robbers  who  had  seized  on 
the  treasure.  Neither  on  the  surface  of  the 
ground,  nor  in  the  workings  at  the  distance  of 
1500  feet  below  it,  was  there  the  slightest 
movement  of  the  earth  perceived.  Over  the 
whole  of  the  Mexican  highlands  no  noise  of  the 
same  kind  had  ever  been  heard  before,  neither 
has  the  alarming  incident  recurred.  Thus  do 
chasms  in  the  interior  of  the  earth  open  and 
close  ;  and  the  sonorous  waves  either  reach  us 
or  are  interrupted  in  their  progress. 

The  influence  of  a  volcanic  mountain  in  ac- 
tion, however  terrific  or  picturesquely  grand  as 
an  object  of  sense,  is  still  always  limited  to  a 
very  narrow  space.  It  is  very  different  with 
the  shocks  of  earthquakes,  which  are  scarcely 
appreciable  to  the  eye,  but  their  undulations  oc- 
casionally extend  simultaneously  to  the  dis- 
tance of  thousands  of  miles.  The  great  earth- 
quake which  desolated  Lisbon  on  the  1st  of 
November,  1755,  and  whose  influences  have 
been  so  admirably  investigated  by  the  great 
philosopher  Emanuel  Kant,  was  felt  among  the 
Alps,  on  the  coast  of  Sweden,  in  the  West  In- 
dian islands,  Antigua,  Barbadoes,  and  Martin- 
ique, and  on  the  great  Canadian  lakes,  as  well 
as  in  the  small  inland  lakes  of  the  basaltic  plains 
of  Thuringia  and  the  northern  flats  of  Germany. 
Distant  springs  were  interrupted  in  their  course, 
an  incident  in  earthquakes  to  which  Demetrius 
the  Galatian  directed  attention  in  ancient  times. 
The  hot  springs  at  Tepliz  ran  dry,  and  then  re- 
turned deeply  tinged  with  a  ferruginous  ochre, 
flooding  every  thing.  At  Cadiz  the  sea  rose 
sixty  feet  high  ;  in  the  lesser  Antilles  it  became 
of  an  inky  black  colour,  and  the  tide,  which 
generally  rises  but  about  twenty-six  or  twenty- 
eight  inches,  mounted  twenty  feet  above  its 
usual  level.  It  has  been  calculated  that  a  ter- 
ritory more  than  four  times  the  superficial  ex- 
tent of  Europe  was  shaken  by  the  earthquake 
of  November  1st,  1755.  There  is,  therefore, 
no  other  outward  manifestation  offeree  known 
— the  murderous  inventions  of  our  race  inclu- 
ded—through which,  in  the  brief  period  of  a 
few  seconds  or  minutes,  a  larger  number  of 
human  beings  have  been  destroyed :  in  1793, 
sixty  thousand  perished  in  Sicily  ;  from  thirty 
to  forty  thousand  fell  victims  in  the  catastrophe 
of  Riobamba  of  1797,  and  perhaps  five  times  as 
many  in  Lesser  Asia  and  Syria  under  Tiberius 
and  Justin  the  Elder,  about  the  years  19  and 
526  of  the  Christian  era. 

There  are  instances  among  the  Andes  of 


M 


EARTHQUAKES. 


South  America  of  the  earth  having  quaked  in- 
cessantly for  several  days  together  ;  but  I  only 
know  of  shocks  that  were  felt  almost  every 
hour  for  several  months,  having  occurred  far 
from  any  volcano^  on  the  eastern  slopes  of  the 
Alps  of  Mont-Genis,  about  Fenestrella  and  Pig- 
nerolo,  from  April,  1808  ;  in  the  United  States 
of  America,  betwixt  New  Madrid  and  Little 
Prairie(^"),  to  the  north  of  Cin9innati,  after 
December,  1811  ;  in  the  Paschalic  of  Aleppo, 
in  the  months  of  August  and  September,  1822. 
As  the  vulgar  mind  can  never  rise  to  general 
views,  and  therefore  always  ascribes  great  phe- 
nomena to  local  processes  of  the  earth  or  of 
the  air,  wherever  succussions  continue  for  any 
length  of  time,  fears  for  the  appearance  of  new 
volcanoes  take  their  rise.  In  single,*  rare  in- 
stances, this  fear  has  indeed  shown  itself  well- 
founded,  as  in  the  ease  of  the  sudden  rise  of 
volcanic  islands,  and  in  the  production  of  the 
volcano  of  Jorullo,  a  new  mountain,  rising  1580 
feet  above  the  old  neighbouring  level,  on  the 
29th  of  September,  1759,  after  ninety  days  of 
earthquakes  and  subterraneous  Ihunderings. 

Could  we  have  daily  news  of  the  state  of  the 
whole  of  the  earth's  surface,  we  should,  in  all 
probability,  become  convinced  that  some  point 
or  another  of  this  surface  is  ceaselessly  sha- 
ken ;  that  there  is  uninterrupted  reaction  of  the 
interior  upon  the  exterior  going  on.  This  con- 
stancy and  general  diffufiion  of  a  phenomenon, 
which  is  probably  connected  with  the  high  tem- 
perature of  the  deepest  strata  of  the  earth,  ex- 
plains its  independence  of  the  nature  of  the 
rocky  masses  among  which  it  is  manifested. 
Shocks  of  an  earthquake  have  been  experien- 
ced even  in  the  loosest  alluvial  deposits  of  Hol- 
land, around  Middleburg  and  Flushing.  Gran- 
ite and  mica  slate  are  shaken  in  the  same  way 
as  mountain  limestone  and  sandstone,  as  tra- 
chytic  and  amygdaloidal  formations.  It  is  not 
the  chemical  nature  of  the  constituents,  but  the 
mechanical  structure  of  the  mineral  species, 
that  modifies  the  propagation  of  the  motion  (the 
wave  of  succussion).  Where  the  wave  pro- 
ceeds regularly  along  a  coast,  or  by  th?  foot, 
and  in  the  direction  of  a  mountain-chain,  it  is 
occasionally  observed  that  there  is  an  interrup- 
tion suffered  at  certain  points.  This  has  been 
noticed  for  centuries.  The  undulation  advan- 
ces along  the  depths,  but  at  the  points  in  ques- 
tion it  is  never  felt  at  the  surface.  The  Peru- 
vians say  of  these  unshaken  superior  strata, 
that  "  they  form  a  bridge"(^*').  As  mountain- 
chains  appear  upheaved  through  fissures,  the 
walls  of  these  cavities  may  very  well  favour  or 
influence  the  course  of  the  undulations  that  run 
parallel  with  the  chain  ;  occasionally,  however, 
the  waves  of  succussion  cut  across  several 
chains,  almost  at  right  angles.  We  thus  see 
them  break  through  the  littoral  chains  of  Vene- 
zuela and  the  Sierra  Parirae  in  South  America. 
In  Asia,  the  earthquakes  of  Lahore  and  the  foot 
of  the  Himalayas  (Jan.  22d,  1832)  were  prop- 
agated transversely  through  the  chain  of  Hin- 
doo-Cusch  to  Badakhchan,  to  the  Upper  Oxus, 
and  even  to  Bokhara(^*°).  Unfortunately,  too, 
the  circles  of  concussion  enlarge,  in  conse- 
quence of  a  single  extremefy  Violent  shock.  It 
is  only  since  the  destruction  of  Cumana  (14th 
Dec.  1797)  that  every  shock  of  the  southern 
coast  is  felt  in  the  mica-slate  strata  of  the  pen- 


insula of  Maniguarez,  which  lies  opposite  the 
limestone  or  chalk-hills  of  the  fortress.  In  the 
almost  incessant  undulations  of  the  ground  of 
the  valleys  of  the  Mississippi,  Arkansas,  and 
Ohio,  which  occurred  from  1811  to  1813,  the 
progress  of  the  motion  from  south  to  north 
was  very  striking.  It  was  as  if  subterranean 
impediments  had  been  gradually  overcome,  and 
the  wave  of  commotion  then  advanced  upon 
each  occasion  along  the  way  which  had  been 
opened  up. 

If  an  earthquake  appear,  at  first  sight,  to  be 
a  phenomenon  of  motion  wholly  dynamical, 
having  reference  to  space  only,  it  is  still  recog- 
nized, on  the  grounds  of  the  most  careful  ex- 
perience, that  it  is  not  only  competent  to  raise 
whole  districts  above  their  old  level  (Ulla-Bund, 
eastward  from  the  delta  of  the  Indus,  for  ex- 
ample, after  the  earthquake  of  Cutch,  in  June, 
1809,  and  the  coast  of  Chili,  in  November, 
1822),  but  farther,  that  during  the  shock,  hot 
water  (Catania,  1818),  hot  steam  (valley  of  the 
Mississippi,  near  New  Madrid,  1812),  mephitic 
or  irrespirable  gases,  which  are  injurious  to  the 
pasturing  herds  and  flocks  of  the  Andes,  mud, 
black  smoke,  and  even  flames  (Messina,  1782, 
Cumana,  14th  Nov.  1797),  have  been  dischar- 
ged. During  the  great  earthquake  of  Lisbon, 
Nov.  1,  1755,  flames  and  a  column  of  smoke 
were  seen  to  rise  from  a  newly- formed  fissure 
in  the  rock  of  Alvidras,  near  the  city.  The 
smoke  became  on  each  occasion  where  it  ap- 
peared, by  so  much  the  more  dense  as  the  sub- 
terraneous noise  increased  in  loudness(^®'). 
When  the  town  of  Riobamba  was  destroyed  in 
1797,  the  earthquake  was  not  accompanied  by 
any  eruption  of  the  volcano  which  is  so  close 
at  hand  ;  but  Moya,  a  singular  mass,  compound- 
ed of  carbon,  crystals  of  augite,  and  the  silice- 
ous coats  of  infusory  animalcules,  was  pushed 
out  of  the  ground  in  numerous  small  and  pro- 
gressive cones.  The  escape  of  carbonic  acid 
gas  during  the  earthquake  of  New  Granada 
(16th  Nov.  1827),  from  fissures  in  the  Magda- 
lena  valley,  caused  the  suffocation  of  many 
snakes,  rats,' and  other  creatures  that  live  in 
holes.  Sudden  changes  in  the  weather,  too, 
the  setting  in  of  the  rainy  season  at  unusual 
periods  in  the  tropics,  have  occasionally  fol- 
lowed great  earthquakes  in  Quito  and  Peru. 
Do  gaseous  fluids,  escaping  from  the  interior 
of  the  earth,  then  become  mingled  with  the  at- 
mosphere 1  or,  are  these  meteorological  pro- 
cesses the  effect  of  a  disturbance  of  the  atmo- 
spherical electricity  by  the  earthquake'?  In 
the  countries  of  tropical  America,  where  some- 
times not  a  drop  of  rain  falls  for  ten  months, 
the  inhabitants  look  upon  repeated  shocks  of 
earthquakes,  which  cause  no  danger  to  their 
low  cane  huts,  as  a  happy  indication  of  plenty 
of  rain,  and  consequently  of  fertility. 

The  intimate  connection  of  all  the  phenom- 
ena now  described  is  still  buried  in  obscurity. 
Elastic  fluids  are  undoubtedly  the  cause,  as 
well  of  the  slight  and  uninjurious  tremblings  of 
the  earth,  which  continue  for  many  days  (as  in 
1816  at  Scaccia,  in  Sicily,  previous  to  the  ele- 
vation of  the  new  island  called  Julia),  as  of  the 
frightful  explosions  which  are  announced  by 
noises.  The  focus  of  the  mischief,  the  seat  of 
the  moving  power,  lies  deep  beneath  the  crust 
of  the  earth  ;  how  deep,  we  know  even  as  little 


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MORSE'S  NEW  PICTORIAL  GEOGRAPHY. 

PRICE  FIFTY  CENTS. 

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EXECUTED  m  THE  NEW  GEROGRAPHIC  PROCESS. 

No  equivecal  evidence  of  the  great  merits  of  this  popular  New  School  Geography' is  afl!brd« 
©d  by  the  faet  that  nearly  one  hundred  thousand  copies  have  been  already  disposed  of  within 
the  brief  interval  of  its  publication.  It  will  be  found  one  of  the  most  beautiful  in  its  pictorial 
embellishments,  lucid  and  simple  in  its  adaptation  to  the  purposes  of  instruction,  as  well  as 
one  of  the  cheapest  ef  all  works  of  the  kind  ever  produced.  The  maps  are  both  novel  and 
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TESTIMONIALS  FROM  THE  PHILADELPHIA  PUBLIC  SCHOOLS. 


Tlie  best  work  on  Geography  in  the  United  States  or 
6reat  Britain:  it  should  find  its  way  into  the  CoKimon 
Schools  and  all  seminaries  of  learning  in  the  TJ.  States. 
Its  admirable  arrangement  and  portability  render  it  an  ei- 
eellent  work  of  reference  ;  no  person  should  be  without  it. 

Amssbw  Gbozibb,  Principal  of  Reed  St.  Gram.  School. 


Ayalnable  acquisition  to  all  engaged  either  in  imparting, 
or  receiving  instruction.  Its  conciseness  and  mmplicity  of 
arrangement,  and  its  numerous  and  beautiful  embellish* 
ments,  Muinot  fail  to  render  it  deservedly  popular. 

"W.  H.  Pile,  Principal  qf  N.  E.  Gram.  School. 


I  kave  examined  with  some  care  the  "  Geography^*  by 
Morse,  and  can  say  that  I  am  particularly  pleased  with  it. 
I  think  it  clear  and  concise  in  its  views,  and  that  the  maps 
and  letter-press  being  in  juxtaposition,  is  a  recommendation 
not  likely  ta  be  passed  by  in  silence.  This  arrangement  is 
calculated  tc  facilitate  the  progress  of  the  learner,  inasmuch 
as  he  has  net  to  look  tc  a  separate  book  for  his  map  :  thus 
time  is  gained,  and  more  ground  gone  over  in  the  same  pe- 
ned.  I  would  therefore  skeerfully  recommend  it  to  all  who 
ftre  in  want  of  such  a  work. 

W.  a.  S.  AoNBw,  Prineipal  of  Zone  St.  Pub.  tthoel. 


We  CMtanr  in  the  opinion  with  Mr.  Agnew. 

James  Rhoass,  Principal  of  N.  W.  Gram.  School. 
A.  T.  W.  Wbioht,  Principal  cf  Model  School. 

I  decidedly  appreve  of  it ;  the  facility  afforded  the  pupil 
(a  referring  to  the  maps,  the  correctness  of  the  political  di- 
visions, and  of  the  population  of  towns  ;  the  eoneiseness  of 
style  and  deecripticn,  and  the  cheapness,  as  well  as  the 
neatness  and  beauty  of  the  typographical  eieeutjon  of  the 
work  are,  in  my  opinion,  strong  recommendations  to  the 
public         W.  W.  Woo»,  Principed  if  S.  W.  Gram.  Soh. 


It  1b  the  best  work  on  the  subject  with  which  I  am  ao- 
qvainted.    It  has  several  advantages  over  ether  works  cf 


the  kind ;  one  is,  that  the  map,  questions  on  the  map,  and 
description  of  each  country,  are  on  the  same  page. 
S.  F.  Watson,  Principal  of  Catherine  St.  Gram.  SchtoL 

I  cheerfully  ecncur  in  the  above  recommendation. 
B.  E.  CHAMBKRLiif ,  Prtn.  of  ButioHttood  St.  Gram.  Seh^ 

Novelty  does  not  necessarily  imply  improvement,  but  in 
this  instance  we  have  an  improvement  by  which  the  efforts 
of  the  young  pupil  will  be  very  much  assisted  in  the  acqui 
sition  of  geographical  knowledge. 

M.  S.  Cleavbnoer,  )  Principals  ef  Locust  St. 

E.  H.  Cox,  J      Gram.  School. 

I  have  examined  the  work,  and  think  it  well  adapted  to 
the  use  of  schools.  Apart  from  the  consideration  that  it« 
descriptions  are  written  in  a  concise,  yet  perspicuous  stylo, 
the  convenient  general  arrangement  of  the  work  and  its  na< 
merons  illustratiens  render  it  superior  to  any  system  of  Ge- 
ography now  in  use. 
L.  0.  Smith,  Prin.  of  T.  Ladies  Gram.  School,  Zone  St. 


It  afibrds  me  pleasure  to  recommend  it  to  teachers  and 
the  public  in  general.  The  arrangement  is  well  planned* 
and  affords  many  facilities  to  the  study  of  geography  that 
were  much  desired.  The  maps  are  certainly  much  supericr 
to  any  thing  of  the  kind  that  has  yet  appeared. 

L.  Hopper,  Principal  <f  Third  St.  School. 

I  have  no  hesitation  in  assigning  to  it  the  first  rank  amen^ 
similar  books  now  in  use  ;  its  excellent  maps,  and  beautiful 
pietorial  illustrations,  are  calculated  to  arrest  the  attention 
of  the  pupil,  and  impress  instruction  indelibly  en  his  mem- 
ory.      Wm.  Robbbts,  Prtn.  of  Moyamtnsing  Gram.  Seh, 


Having  examined  "  Morsels  School  Geography,''^  we  thfak 

it  admirably  calculated  to  carry  out  the  views  of  its  author 

P.  A.  Cresor,  Principal  of  S.  S.  Gram.  School 

S.  D.  JOHNSTOIT. 

L.  N.  BoswBLI. 


HARPER  &  BROTHERS,  PUBLISHERS,  NEW-YORK. 


AKB   MAT   BS   OBTAINED    OF   THB   BOOKSELLERS   THROUOHOVT   THS   VNITCD    STAISaw 


EARTHQUAKES. 


65 


as  we  do  what  the  chemical  nature  of  the  va- 
pour of  such  high  tension  may  be.  Encamped 
on  the  edge  of  two  craters,  on  Vesuvius,  and 
on  the  castellated  rock  which  overlooks  the 
vast  gorge  of  Pichincha,  near  Quito,  I  expe- 
rienced periodical  and  very  regular  shocks, 
and,  each  time,  from  20  to  30  seconds  before 
red-hot  ashes  or  vapours  were  ejected.  The 
shocks  were  by  so  much  the  stronger  as  the 
explosions  were  later  of  occurring,  and  the  va- 
pour consequently  had  been  longer  accumula- 
ting. In  this  simple  fact,  confirmed  by  the  ex- 
perience of  so  many  travellers,  lies  the  general 
solution  of  the  phenomenon.  Active  volcanoes 
are  to  be  regarded  as  safety-valves  for  sur- 
rounding districts.  The  danger  of  the  earth- 
quake increases  when  the  opening  of  the  vol- 
cano is  stopped  up,  and  there  is  no  longer  a 
free  communication  with  the  atmosphere  ;  but 
the  destruction  of  Lisbon,  of  Caraccas,  Lima, 
Cashmir  (1554)^",  and  of  so  many  towns  of 
Calabria,  Syria,  and  Asia  Minor,  teaches  us, 
that  on  the  whole  the  force  of  earthquakes  is 
by  no  means  greatest  in  the  vicinity  of  still  ac- 
tive volcanoes. 

As  the  pent-up  force  of  a  volcano  acts  in 
shaking  the  ground,  so  does  the  concussion  re- 
act, in  its  turn,  upon  the  volcanic  phenomenon. 
The  occurrence  of  fissures  favours  the  rise  of 
the  cones  through  which  eruptions  take  place, 
and  the  processes  which  go  on  within  these 
cones  in  free  contact  with  the  atmosphere.  A 
column  of  smoke,  which  had  been  seen  for 
months  rising  from  the  volcano  of  Pasto,  in 
South  America,  disappeared  suddenly  on  the 
occurrence  of  the  great  earthquake  of  Riobam- 
ba,  in  the  province  of  Quito,  art  the  distance  of 
48  geographical  miles  to  the  south  (Feb.  4, 
1797).  After  the  earth  had  long  continued  to 
tremble  in  the  whole  of  Syria,  in  the  Cyclades, 
and  in  Cuhcea,  the  convulsions  ceased  suddenly 
upon  the  eruption  of  a  stream.of"  red-hot  mud" 
(lava  from  a  crack)  in  the  Lelantine  plain,  near 
Chalcis("3).  The  admirable  geographer  of 
Amasia,  who  has  preserved  the  record  of  this 
fact,  adds :  "  Since  the  mouths  of  Etna  have 
been  opened,  through  which  the  fire  belches 
forth,  and  since,  in  this  way,  heated  masses 
and  water  can  be  ejected,  the  lands  by  the  sea- 
shore are  no  longer  so  frequently  shaken  as 
they  were  in  times  before  the  separation  of 
Sicily  from  Lower  Italy,  when  there  was  no 
communication  with  the  surface." 

In  earthquakes,  therefore,  we  have  evidence 
of  a  volcano-producing  force  ;  but  such  a  force, 
as  universally  diffused  as  the  internal  heat  of 
the  globe,  and  proclaiming  itself  everywhere, 
rarely  gets  the  length  of  actual  eruptive  phe- 
nomena ;  and  when  it  does  so,  it  is  only  in 
isolated  and  particular  places.  The  formation 
of  extensive  veins  or  dykes,  in  other  words,  the 
filling  up  of  fissures  with  crystalline  matter 
ejected  from  the  interior,  such  as  basalt,  mela- 
phyre,  and  greenstone,  interferes  by  degrees 
with  the  free  escape  of  vapours ;  which,  con- 
fined, become  operative,  through  their  tension, 
in  three  ways  :  concussively ;  explosively,  or  sud- 
denly up  and  down  ;  and,  as  first  observed  in  a 
large  portion  of  Sweden,  liftingly  or  continu- 
ously, and  only  in  long  periods  of  time  per- 
ceptibly altering  the  relative  level  of  the  sea 
and  land. 
I 


Before  we  quit  this  great  phenomenon,  which 
has  been  here  considered  not  so  much  in  its  in- 
dividual as  in  its  general  physical  and  geognos- 
tical  relations,  we  must  advert  to  the  cause  of 
the  indescribable,  deep,  and  quite  peculiar  im- 
pression which  the  first  earthquake  we  experi- 
ence makes  upon  us,  even  when  it  is  accom- 
panied by  no  subterranean  noises.  The  impres- 
sion here  is  not,  I  believe,  the  consequence  of 
any  recollection  of  destructive  catastrophes 
presented  to  our  imagination  by  narratives  of 
historical  events  :  what  seizes  upon  us  so  won- 
derfully is  the  disabuse  of  that  innate  faith  in 
the  fixity  of  the  solid  and  sure-set  foundations 
of  the  earth.  From  early  childhood  we  are 
habituated  to  the  contrast  between  the  mobile 
element,  water,  and  the  immobility  of  the  soil 
on  which  we  stand.  All  the  evidences  of  our 
senses  have  confirmed  this  belief  But  when 
suddenly  the  ground  begins  to  rock  beneath  us, 
the  feeling  of  an  unknown  mysterious  power  in 
nature  coming  into  action,  and  shaking  the  solid 
globe,  arises  in  the  mind.  The  illusion  of  the 
whole  of  our  earlier  life  is  annihilated  in  an  in- 
stant. We  are  undeceived  as  to  the  repose  of 
nature,  we  feel  ourselves  transported  to  the 
realm,  and  made  subject  to  the  empire,  of  de- 
structive unknown  powers.  Every  sound — the 
slightest  rustle  in  the  air — sets  attention  on  the 
stretch.  We  no  longer  trust  the  earth  upon 
which  we  stand.  The  unusual  in  the  phenom- 
enon throws  the  same  anxious  unrest  and 
alarm  over  the  lower  animals.  Swine  and  dogs 
are  particularly  affected  by  it ;  and  the  very 
crocodiles  of  the  Orinoco,  otherwise  as  dumb 
as  our  little  lizards,  leave  the  shaken  bed  of  the 
stream  and  run  bellowing  into  the  woods. 

To  man  the  earthquake  presents  itself  as  an 
all-pervading  unlimited  something.  We  can  re- 
move from  an  active  crater  ;  from  the  stream 
of  lava  that  is  pouring  down  upon  our  dwelling 
we  can  escape ;  with  the  earthquake  we  feel 
that  whithersoever  we  fly  we  are  still  over  the 
hearth  of  destruction.  Such  a  mental  condition, 
though  evoked  in  our  very  innermost  nature,  is 
not,  however,  of  long  duration.  When  a  series 
of  slighter  shocks  occur  in  a  district  one  after 
another,  every  trace  of  alarm  soon  vanishes 
among  the  inhabitants.  On  the  rainless  coasts 
of  Peru  nothing  is  known  of  hail,  nor  of  explo- 
sions of  lightning  and  rolling  thunder  in  the 
bosom  of  the  atmosphere.  The  subterraneous 
noise  that  accompanies  the  earthquake  there 
comes  in  lieu  of  the  thunder  of  the  clouds.  Use 
and  wont  for  a  series  of  years,  and  the  very 
prevalent  opinion  that  dangerous  earthquakes 
are  only  to  be  apprehended  two  or  three  times 
in  the  course  of  a  century,  lead  the  inhabitants 
of  Lima  scarcely  to  think  more  of  a  slight  shock 
of  an  earthquake  than  is  thought  of  a  hail-storm 
in  the  temperate  zone. 

Having  now  taken  a  general  survey  of  the 
activity,  and  likewise  of  the  internal  life  of  the 
globe  :  in  its  contained  heat,  in  its  electro-mag- 
netic tension,  in  its  luminous  emanations  at  the 
poles,  in  its  irregularly-recurring  phenomenon 
of  motion,  we  come  to  elementary  material 
PRODUCTION,  to  chemical  changes  in  the  crust 
of  the  earth,  and  in  the  composition  of  the  at- 
mosphere, which  are  in  like  manner  the  conse- 
quence of  planetary  vital  activity.    From  the 


66 


HOT  SPRINGS. 


ground  we  see  effusions  :  of  watery  vapour  and 
of  gaseous  carbonic  acid,  mostly  free  from  all 
admixture  of  azote("*) ;  of  carburetted  hydro- 
gen gas  (in  the  Chinese  province  of  Sse-Tschu- 
an("*)  for  thousands  of  years,  and  in  the  State 
of  New  York,  where,  in  the  village  of  Fredonia, 
it  has  lately  been  employed  for  economical  pur- 
poses in  heating  and  lighting ;  of  sulphuretted 
hydrogen  gas ;  of  sulphur  fumes,  and  more 
rarely  of  sulphurous  and  hydrochloric  acid  va- 
pours(^").  Such  emanations  from  fissures  in 
the  ground  do  not  only  indicate  the  dominion 
of  volcanoes  long  extinct  or  still  burning  ;  they 
are  farther  observed  exceptionally  in  districts 
in  which  neither  trachyte  nor  any  other  volcanic 
rock  meets  the  eye  exposed  upon  the  surface. 
In  the  Andes  of  Quindiu  I  have  seen  sulphur 
precipitated  from  hot  sulphureous  vapours  issu- 
ing out  of  mica  slate,  at  a  height  of  6410  feet 
above  the  level  of  the  sea('^^) ;  whilst  the  same, 
and,  as  it  used  to  be  regarded,  primitive  rock, 
in  the  Cerra  Cuelo,  near  Ticsan,  south  of  Quito, 
exhibits  an  enormous  bed  of  sulphur  in  pure 
quartz. 

Of  all  the  air-springs  which  the  earth  pours 
forth,  those  of  carbonic  acid  gas  are  still  at  the 
present  time  the  most  important  both  in  num- 
ber and  extent.  Germany,  in  her  deeply-cut 
valleys  of  the  Eifel,  in  the  neighbourhood  of 
Lake  Lach,  in  the  Kesselthal  of  Wehr,  and  in 
Western  Bohemia,  as  also  in  the  burning  hearths 
of  the  primeval  world,  or  their  vicinity,  shews 
us  these  effusions  of  carbonic  acid  as  a  kind 
of  last  effort  of  volcanic  activity.  In  former 
epochs,  where,  with  a  higher  temperature  of 
the  earth,  and  the  frequency  of  fissures  yet  un- 
filled, the  processes  which  we  are  here  descri- 
bing proceeded  more  actively,  where  carbonic 
acid  gas  and  watery  vapours  were  mingled  with 
the  atmosphere  in  larger  quantities  than  at 
present,  the  youthful  vegetable  world,  as  Adolph 
Brongniart("8)  has  acutely  observed,  must  have 
attained  almost  everywhere,  and  independently 
of  geographical  position,  to  the  most  rank  lux- 
uriance and  evolution  of  its  organs.  In  the 
ever  hot,  ever  moist  atmosphere,  surcharged 
with  carbonic  acid,  vegetables  must  have  found 
such  vital  excitement,  such  superfluity  of  nour- 
ishment, as  enabled  them  to  supply  the  material 
of  those  beds  of  coal  and  lignite,  the  exhaustion 
of  which  it  is  difficult  to  conceive,  and  which 
now  serve  as  foundations  for  the  physical 
strength  and  the  welfare  of  nations.  Such  beds 
are  principally  contained  in  basins,  and  are  pe- 
culiar to  certain  parts  of  Europe.  They  are 
abundant  in  the  British  Isles,  in  Belgium,  in 
France,  on  the  Nether  Rhine,  and  in  Upper 
Silesia.  In  the  same  primeval  times  of  all- 
pervading  volcanic  action,  too,  must  those  enor- 
mous quantities  of  carbonaceous  matter  have 
issued  from  the  bowels  of  the  earth  which  all 
the  limestone  rocks  contain,  and  which,  separ- 
ated from  oxygen,  and  represented  in  the  solid 
form,  composes  about  an  eighth  part  of  the  ab- 
solute bulk  of  these  great  mountain  masses 
("^).  The  carbonic  acid  which  the  atmosphere 
still  contained,  and  which  was  not  absorbed  by 
the  alkaline  earths,  was  gradually  consumed 
by  the  vegetation  of  the  primeval  world,  so  that 
the  atmosphere,  purified  by  the  processes  of 
vegetable  life,  by  and  by  contained  no  more  of 
the  gas  than  was  uninjurious  to  the  organiza- 


tion of  such  animals  as  people  the  earth  at  tho 
present  time.  Sulphurous  or  sulphuric  acid 
vapours,  too,  occurring  more  frequently  and 
much  more  abundantly  ihea  than  now,  occa- 
sioned the  destruction  of  the  inhabitants  of  the 
inland  waters — mollusca  and  numerous  genera 
of  fishes,  as  well  as  the  formation  of  the  strange- 
ly-twisted beds  of  gypsum  which  have  often 
apparently  been  shaken  by  earthquakes. 

Under  precisely  similar  physical  relations 
there  were  further  thrown  out  from  the  bosom 
of  the  ground  various  gases  and  liquids,  mud, 
and,  from  the  eruption-cones  of  volcanoes, 
which  are  but  a  species  of  intermitting  springs, 
streams  of  molten  earths(^"*).  All  these  mat- 
ters owe  their  temperature  and  the  nature  of 
their  chemical  constitution  to  the  place  of  their 
origin.  The  mean  temperature  of  ordinary 
springs  is  lower  than  that  of  the  atmosphere 
of  the  place  where  they  appear,  when  the  wa- 
ter is  derived  from  high  levels  ;  their  tempera- 
ture increases  with  the  depth  of  the  strata  with 
which  they  come  in  contact  at  their  origin. 
The  numerical  law  of  this  increase  has  been 
stated  above.  The  mixture  of  the  waters  which 
come  from  the  mountain  elevations  and  from 
the  depths  of  the  earth,  renders  the  position  of 
the  isogeothermal  lines(^'*),  or  Hues  of  like  in- 
ternal heat  of  the  earth,  difficult  of  determina- 
tion, when  the  conclusion  has  to  be  come  to 
from  the  temperature  of  springs  as  they  rise. 
So,  at  least,  did  I  and  my  friends  find  it  in  some 
experiments  which  we  made  in  Northern  Asia. 
The  temperature  of  springs,  which  has  been  so 
constant  an  object  of  physical  investigation  for 
the  last  half  century,  depends,  like  the  height  of 
the  line  of  perpetual  snow,  on  numerous  and 
highly  complex  causes.  It  is  a  function  of  the 
temperature  of  the  stratum  in  which  they  have 
their  origin,  of  the  capacity  for  heat  of  the  ground, 
and  of  the  quantity  and  temperature  of  the  at- 
mospheric or  meteoric  water  that  falls(*"), 
which  last,  again,  according  to  the  mode  of  its 
origin,  differs  in  its  temperature  from  that  of 
the  lower  strata  of  the  atmosphere(i''^). 

Gold  springs,  as  they  are  called,  can  only  give 
the  mean  temperature  of  the  air  if  unmixed 
with  water  that  is  rising  from  great  depths,  or 
that  is  descending  from  considerable  heights, 
and  when  they  have  flowed  for  a  very  long  way 
under  the  surtace  of  the  earth — in  our  latitudes 
from  40  to  60  feet,  in  the  equinoctial  zone,  ac- 
cording to  Boussingault,  one  foot(^^*).  These 
depths  are  those,  in  fact,  of  the  stratum  of  earth 
in  which,  in  the  temperate  and  torrid  zone  re- 
spectively, the  point  of  invariable  temperature 
begins,  in  which  the  hourly,  diurnal,  or  month- 
ly variations  in  temperature  of  the  air  are  no 
longer  perceived. 

Hot  springs  burst  out  of  the  most  diversified 
mineral  strata ;  the  hottest  of  all  the  perma- 
nent spnngs  which  have  yet  been  observed, 
and  which  I  myself  discovered,  flow  remote 
from  all  volcanoes.  I  here  refer  to  the  Aguas 
calientes  de  las  Trincheras,  between  Puerto 
Cabello  and  New  Valencia,  and  to  the  Aguas 
de  Comangillas,  near  Guanaxuato  in  Mexico. 
The  first  spring,  issuing  from  granite,  indicated 
90-3°  C. ;  the  second,  which  breaks  from  basalt, 
shewed  96-4°  C.  The  depth  of  the  source  of 
water  of  these  temperatures,  from  what  we 
know  of  the  law  of  increase  of  temperature  in 


HOT  SPRINGS.— MUD  VOLCANOES. 


67 


the  interior  of  the  earth,  must  probably  be  about 
6700  feet  (more  than  half  a  geographical  mile). 
If  the  cause  of  the  heat  of  thermal  springs,  as 
well  as  of  active  volcanoes,  be  the  universally 
diffused  heat  of  the  earth,  then  would  mineral 
species  produce  an  effect  only  through  their  ca- 
pacity for,  and  their  power  of  conducting  heal. 
The  hottest  of  all  the  permanent  springs,  those, 
namely,  from  95«  to  97°  C.  (204°  to  207-6°  F.), 
it  is  remarkable,  are  the  purest,  are  those  that 
contain  the  smallest  quantity  of  mineral  matter 
in  solution.  Their  temperature  appears  on  the 
whole  to  be  less  permanent  than  that  of  springs 
between  50°  and  74°  C,  the  invariableness  of 
which,  both  in  regard  to  temperature  and  min- 
eral impregnation,  has  been  maintained  so  won- 
derfully, within  the  confines  of  Europe  at  least, 
during  the  last  fifty  or  sixty  years,  i.  e,  since  ac- 
curate thermometrical  observations  and  chem- 
ical analyses  were  made.  Boussingault  found 
that  the  thermal  springs  of  las  Trincheras  had 
risen  in  temperature  in  the  course  of  twenty- 
three  years  (from  1800,  when  my  journey  was 
performed,  to  1823),  from  93-3°  to  97°  C.(^'5). 
This  very  smoothly  flowing  spring  is  conse- 
quently at  this  time  7°  C.  higher  in  tempera- 
ture than  the  intermitting  Geyser  and  Strokr, 
the  temperature  of  which  has  been  lately  very 
carefully  ascertained  by  Krug  of  Nidda.  One 
of  the  most  remarkable  proofs  of  the  origin  of 
these  hot  springs  being  due  to  the  percolation 
of  cold  meteoric  water  into  the  interior  of  the 
earth,  and  its  contact  there  with  a  volcanic  fo- 
cus, was  presented  in  the  preceding  century  in 
connection  with  the  volcano  of  Jorullo  in  Mex- 
ico, which  was  unknown  to  geography  till  after 
my  South  American  journey.  When  this  mount- 
ain suddenly  made  its  appearance  in  September, 
1759,  rising  to  a  height  of  1580  feet  above  the 
surrounding  level,  the  two  small  streams,  Rios 
de  Cuitimba  y  de  San  Pedro  disappeared  ;  but 
by  and  by  they  made  their  appearance  again, 
under  the  dreadful  shocks  of  an  earthquake,  as 
hot  springs.  In  1803  I  found  their  temperature 
65-8°  C. 

The  springs  of  Greece  still  flow  apparently 
in  the  same  places  as  they  did  in  the  times  of 
Hellenic  antiquity.  The  source  of  Erasinos, 
two  leagues  south  of  Argos,  on  the  declivity  of 
Chaon,  is  even  mentioned  by  Herodotus.  At 
Delphi,  the  Cassotis,  under  its  name  of  Stream, 
of  St.  Nicholas,  still  rises  to  the  south  of  the 
Lesche,  and  flows  under  the  Temple  of  Apollo ; 
the  Castalia,  too,  at  the  foot  of  the  Phaedriadae, 
and  the  Pirene  at  Acrocorinth,  are  there,  as 
well  as  the  hot  baths  of  ^depsum  in  Cubcea, 
in  which  Sulla  bathed  at  the  time  of  the  Mithri- 
datic  war(^^«).  I  gladly  adduce  these  particu- 
lars, because  they  forcibly  remind  us  how,  in  a 
country  exposed  to  earthquakes  so  frequent  and 
so  violent,  the  interior  of  our  planet  has  been 
able  to  preserve  its  fashion  for  2000  years  at 
least ;  the  small,  branching,  and  open  fissures 
that  convey  the  water  of  these  springs  have  not 
altered.  The  Fontaine  jaillissanle  of  liillers  in 
the  department  of  the  Pas  de  Calais,  was  bored 
in  the  year  1126,  and  ever  since  then  has  the 
water  flowed  uninterruptedly  to  the  same  height, 
and  in  the  same  quantity ;  the  excellent  geog- 
rapher of  the  Caramanian  coasts,  Captain  Beau- 
fort, moreover,  observed  the  same  flame,  fed  by 
a  stream  of  inflammable  gas,  which  escapes  in 


the  district  of  Phaselis,  which  Pliny(^")  de- 
scribes as  the  flame  of  Chimaera  in  Lycia. 

The  observation  made  by  Arago  in  1821,  that 
the  deeper  Artesian  wells  are  the  warmer(^^^), 
was  the  first  means  of  throwing  a  great  light 
I  upon  the  origin  of  thermal  springs,  and  led  to 
]  the  discovery  of  the  law  of  the  increase  of  the 
temperature  of  the  earth  according  to  the  depth. 
It  is  remarkable,  and  only  noticed  in  very  re- 
cent times,  that  St.  Patricius("'),  probably  bish- 
op of  Pertusa,  was  led  to  a  very  correct  view 
of  the  phenomenon  which  presented  itself  in 
the  appearance  of  the  hot  springs  near  Carthage 
at  the  end  of  the  third  century.  When  ques- 
tioned as  to  the  cause  of  the  boiling  hot  water 
which  poured  out  from  the  earth,  he  answered  : 
"  Fire  is  nourished  in  the  clouds  and  in  the  in- 
terior of  the  earth,  as  Etna,  and  another  mount- 
ain in  the  neighbourhood  of  Naples,  inform  you. 
The  subterranean  waters  rise  as  through  sy- 
phons;  and  the  cause  of  the  heat  of  hot  springs 
is  this  :  the  waters  that  are  more  remote  from 
the  subterraneous  fire  show  themselves  colder ; 
those  that  flow  in  closer  proximity  to  the  fire, 
warmed  by  it,  bring  an  insupportable  heat  to 
the  surface  which  we  inhabit." 

As  earthquakes  are  frequently  accompanied 
by  eruptions  of  water  and  watery  vapour,  so  do 
we  perceive  in  the  volcanoes  that  pour  out  mud 
a  transition  from  the  alternating  phenomena 
I  presented  by  jets  of  vapour  and  thermal  springs 
I  to  the  grand  and  destructive  activity  of  the 
mountains  that  vomit  lava.  If  these,  as  springs 
of  melted  earths,  produce  volcanic  rocks,  so  do 
the  thermal  springs  that  are  charged  with  car- 
bonic acid  and  sulphurous  gas  [and  earthy  mat- 
ters], produce  by  incessant  precipitation  either 
horizontal  beds  of  limestone  (travertin),  or  they 
form  conical  hillocks,  as  in  the  north  of  Africa 
(Algeria),  and  the  Baiios  of  Caxamarca,  on  the 
western  declivity  of  the  Peruvian  Andes.  In 
the  travertin  of  Van  Dieman's  Land,  not  far 
from  Hobart  Town,  they  are  contained,  accord- 
ing to  Mr.  Charles  Darwin,  the  remains  of  an 
extinct  flora.  By  lava  and  travertin,  two  spe- 
cies of  rock  the  production  of  which  goes  on 
under  our  eyes,  we  here  indicate  the  grand  an- 
titheses in  geognostical  relations. 

Mud  volcanoes  (Salsen)  deserve  a  greater 
share  of  attention  than  geologists  have  hitherto 
bestowed  upon  them.  The  extent  of  the  phe- 
nomenon has  been  overlooked,  because  in  the 
two  states  in  which  it  presents  itself  to  us,  the 
one  of  repose  is  that  which  has  been  principal- 
ly dwelt  upon,  and  in  this  state  of  repose  mud 
volcanoes  often  continue  for  centuries.  The 
production  of  mud  volcanoes  is  accompanied  by 
earthquakes,  subterranean  thunder,  the  eleva- 
tion of  a  whole  district  of  country,  and  the 
eruption  of  flames,  which  rise  high,  but  last  only 
for  a  short  time.  When  the  mud  volcano  of 
Iskmali  made  its  appearance  in  the  peninsula  of 
Abscheron,  eastward  from  Baku,  on  the  Cas- 
pian Sea  (on  the  27th  of  November,  1827), 
flames  burst  forth,  and  blazed  up  to  an  extra- 
ordinary height  for  a  period  of  three  hours  ;  for 
the  next  succeeding  twenty  hours  they  scarcely 
rose  three  feet  above  the  surface  of  the  crater 
that  discharged  the  mud.  The  column  of  flame 
mounted  to  such  a  height  near  the  village  of 
Baklichi,  westward  from  Baku,  that  it  was  seen 


MUD  VOLCANOES.— VOLCANOES. 


at  the  distance  of  six  [German]  miles.  Great 
blocks  of  stone,  torn  from  their  foundations  be- 
neath, were  scattered  widely  around.  Similar 
blocks  are  observed  about  the  now  slumbering 
mud  volcanoes  of  Monte  Zibio,  near  Sassuolo, 
in  the  north  of  Italy.  The  second  state,  or 
that  of  activity,  has  continued  for  1500  years 
in  the  mud  volcano  of  Girgenti  (Macalubi),  in 
Sicily,  which  is  described  by  the  ancients. 
Many  conical  hillocks  of  8,  10,  and  even  30 
feet  high,  though  the  height  as  well  as  the  form 
of  these  varies  at  different  times,  are  there  seen 
arranged  near  one  another.  From  the  superior 
very  small  basin,  which  is  full  of  water,  along 
with  periodic  escapes  of  gas,  there  are  periodic 
streams  of  clayey  mud  discharged.  The  mud 
of  these  volcanoes  is  generally  cold,  but  oc- 
casionally, as  at  Damak,  in  the  province  of 
Samarang,  island  of  Java,  it  is  of  high  tem- 
perature. The  gases,  which  escape  with  a 
rushing  noise,  are  also  of  different  kinds — hy- 
drogen gas,  mixed  with  naphtha,  carbonic  acid, 
and,  as  Parrot  and  I  ascertained  (in  the  penin- 
sula of  Taman  and  the  South  American  Vol- 
cancitos  de  Turbaco),  almost  pure  nitrogen 
gas(^«°). 

Mud  volcanoes,  after  the  first  forcible  out- 
burst of  flame,  which  perhaps  is  not  common  to 
all  in  the  same  measure,  present  the  observer 
with  a  picture  of  sn  activity  of  the  interior  of 
the  earth  that  proceeds  incessantly  but  feebly. 
The  communication  with  the  deep  strata  in 
which  a  high  temperature  prevails  is  speedily 
interrupted  again ;  and  the  cold  discharges  of 
mud  volcanoes  seem  to  indicate  that  the  seat 
of  the  phenomenon,  in  its  state  of  continuance, 
cannot  be  very  remote  from  the  surface.  The 
reaction  of  the  interior  of  the  earth  upon  its 
outer  crust  is  exhibited  in  a  very  different  de- 
gree of  force  in  the  proper  volcanoes,  or  burn- 
ing mountains  ;  in  other  words,  in  those  points 
of  the  earth  where  a  permanent  communica- 
tion, or,  at  all  events,  a  communication  that  is 
renewed  from  time  to  time,  is  established  be- 
tween the  surface  and  the  deep  focus  of  igni- 
tion. We  must  carefully  distinguish  between 
more  or  less  exaggerated  volcanic  phenomena, 
such  as  these  :  Earthquakes,  hot  springs  and 
jets  of  steam,  mud  volcanoes,  the  appearance 
of  unopened  dome-shaped  trachytic  mountains, 
the  opening  of  these  mountains,  or  the  upheaval 
of  basaltic  beds  as  craters  of  elevation,  the 
final  rise  of  a  permanent  volcano  within  the 
upheavement  crater  itself,  or  amongst  the  frag- 
ments of  its  previous  constitution.  At  differ- 
ent times,  along  with  different  degrees  of  ac- 
tivity and  force,  permanent  volcanoes  throw 
out  jets  of  aqueous  vapour,  acids,  glowing 
ashes  and  scoriae,  and,  when  the  resistance  can 
be  overcome,  fiery  streams  of  melted  earthy 
matters. 

As  a  consequence  of  a  great  but  local  mani- 
festation of  force  in  the  interior  of  our  planet, 
elastic  vapours  raise  either  single  parts  of  the 
crust  of  the  earth  into  dome-shaped,  unopened 
masses  of  felspathic  trachyte  and  dolerite  (Puy 
de  Dome  and  Chimborazo) ;  or  the  upheaved 
strata  are  broken  through,  and  inclined  out- 
wards in  such  wise  that  upon  the  opposite  inner 
aspect  a  steep  rocky  edge  is  produced.  This 
edge  then  becomes  the  boundary  of  an  upheave- 
ment crater.    When  this  has  risen  from  the 


bottom  of  the  sea,  which  does  not  by  any  means 
happen  in  every  case,  it  then  presents  the 
whole  of  the  characteristic  physiognomy  of  the 
upheaved  island.  This  is  the  origin  of  the  cir- 
cular form  of  Palma,  which  Leopold  von  Buch 
has  described  so  carefully  and  so  ably,  as  well 
as  of  Nisyros,  in  the  .^gean  Sea("^).  Occa- 
sionally, one  half  the  ring-like  edge  is  destroy- 
ed, and  in  the  bay  which  the  sea  that  has  flow- 
ed in  then  forms,  the  social  coral  insects  es- 
tablish themselves,  and  produce  their  cellular 
dwellings.  Craters  of  elevation  on  continents 
are  also  frequently  found  filled  with  water, 
when  they  contribute  to  beautify  the  landscape 
in  an  extraordinary  and  quite  peculiar  manner. 
Their  origin  is  not  connected  with  any  spe- 
cial mountain  formations ;  they  break  out  in 
basalt,  trachyte,  and  leucitic  porphyry  (Somma), 
or  in  doleritic  mixtures  of  augite  and  labrador. 
Hence  the  very  dissimilar  natures  and  external 
forms  of  this  kind  of  crater  edge.  "  No  erup- 
tive phenomena  take  place  from  such  bounda- 
ries ;  through  them  there  is  no  permanent  chan- 
nel of  communication  established  with  the  in- 
terior, and  it  is  only  very  rarely  that  traces  of 
still  active  volcanic  power  are  discovered  in 
the  precincts  or  within  the  circuit  of  such  cra- 
ters. The  force  competent  to  bring  about  such 
important  effects  must  long  have  gathered  it- 
self together,  and  gained  strength  in  the  inte- 
rior, before  it  could  overcome  the  resistance  of 
the  superincumbent  masses.  On  the  formation 
of  new  islands,  it  throws  up  granular  rocky 
masses,  and  conglomerates  (layers  of  tufa  full 
of  marine  plants)  above  the  level  of  the  sea. 
Compressed  gases  escape  through  the  crater 
of  elevation  ;  but  a  mass  of  such  magnitude 
thus  upheaved  sinks  down  again,  and  closes 
forthwith  the  openings  which  are  only  formed 
for  such  manifestations  of  force.  No  volcano 
is  produced"(i«2) 

A  proper  volcano  only  arises  where  a  per- 
manent connection  is  established  between  the 
interior  of  the  earth  and  the  atmosphere.  Here 
the  reaction  of  tMfe  interior  upon  the  exterior 
proceeds  for  lengthened  periods.  It  may,  as 
in  the  case  of  Vesuvius  (Fisove)^^^  be  inter- 
rupted for  centuries,  and  exhibit  itself  anew 
with  renovated  vigour.  In  the  time  of  Nero  it 
was  already  customary,  in  Rome,  to  rank  .^tna 
among  the  number  of  the  gradually-expiring 
volcanic  mountains(^^*)  ;  JSlian,  indeed,  at  a 
later  period,  maintained  that  the  seamen  began 
to  see  the  sinking  summit  at  a  less  distance  on 
the  high  seas  than  formerly(^^*).  Where  the 
evidence  of  the  eruption,  I  might  say  the  old 
scaffolding,  has  been  perfectly  preserved,  the 
volcano  shows  itself  rising  from  a  crater  of  el- 
evation ;  there  a  high  rocky  wall,  a  rampart  of 
greatly-inclined  strata,  surrounds  the  isolated 
cone  in  the  manner  of  a  circus.  Sometimes 
there  is  not  a  trace  of  this  circus-like  inclosure 
visible,  and  the  volcano,  not  always  conical  in 
figure,  then  arises  as  an  elongated  ridge  imme- 
diately from  the  elevated  platform.  This  is 
the  case  with  Pichincha,  at  the  foot  of  which 
stands  the  city  of  Quito. 

As  the  nature  of  mountain  masses,  in  other 
words,  the  combination  or  grouping  of  simple 
minerals  into  granite,  gneiss,  and  mica-slate, 
into  trachyte,  basalt,  and  dolerite,  independent- 
ly of  present  climates,  and  under  the  most  dis- 


VOLCANOES. 


69 


similar  zones,  is  still  the  same  ;  so  do  we  ev- 
erywhere observe  the  same  laws  of  formation 
proclaiming  themselves  in  the  realm  of  inor- 
ganic nature,  laws  according  to  which  the 
strata  of  the  crust  of  the  earth  stand  in  a  cer- 
tain relationship  to  one  another,  under  the  in- 
fluence of  elastic  forces,  and  break  through  one 
another  as  dykes.  This  recurrence  of  the  same 
phenomena  is  particularly  striking  in  volcanoes. 
When  the  navigator,  among  the  islands  of  dis- 
tant seas,  finds  himself  surrounded  by  palms 
and  strange  forms  of  vegetation,  and  no  longer 
sees  the  same  stars,  in  the  individualities  of 
the  landscape  he  still  traces  Vesuvius,  the 
dome-shaped  summit  of  Auvergne,  the  craters 
of  elevation  of  the  Canaries  and  Azores,  the 
fissures  of  eruption  of  Iceland  repeated  and  re- 
flected ;  a  glance  at  the  attendant  of  our  planet, 
the  moon,  generalizes  still  farther  the  analogy 
of  formation  here  adverted  to.  In  the  maps  of 
the  moon,  drawn  from  the  image  reflected  in 
powerful  telescopes,  in  our  satellite,  without 
atmosphere  and  without  water,  we  can  distin- 
guish vast  craters  of  elevation,  which  surround 
conical  mountains,  or  support  them  on  their 
circular  walls :  unquestionable  effects  of  the 
reaction  of  the  interior  of  the  moon  upon  her 
exterior,  aided  by  the  influence  of  diminished 
gravity. 

If  in  many  languages  volcanoes  are  very 
properly  designated  Burning  Mountains,  it 
would  still  be  a  great  mistake  to  suppose  that 
they  were  produced  by  any  gradual  accumula- 
tion of  the  streams  of  lava  that  have  flowed 
from  them  ;  their  origin  appears  to  be  much 
more  generally  the  consequence  of  a  sudden 
upheaval  of  tenacious  masses  of  trachyte  or 
augitic  rock,  including  Labrador  spar.  The 
measure  of  the  upheaving  force  reveals  itself 
in  the  height  of  the  volcano  ;  and  this  is  so  dif- 
ferent, that  in  one  case  it  is  a  mere  hillock  (as 
in  Cosima,  one  of  the  Japanese  Kuriles),  in  an- 
other it  is  a  cone  that  rises  to  a  clear  elevation 
of  18,000  feet.  It  has  seemed  to  me  as  if  the 
relative  height  had  a  great  influence  upon  the 
frequency  of  the  eruptions ;  as  if  these  were 
much  more  common  in  the  lower  than  in  the 
loftier  volcanoes.  I  will  call  attention  to  the 
following  series:  Stromboli  (2,175  feet  high), 
Guacamayo,  in  the  province  of  Quiros,  which 
thunders  almost  every  day  (I  have  frequently 
heard  it  in  Chillo,  near  Quito,  at  a  distance  of 
22  miles),  Vesuvius  (3,637  feet  high),  ^tna 
(10,200  feet  high),  the  Peake  of  Teneriffe 
(11,424  feet  high),  and  Cotopaxi  (17,892  feet 
high).  If  the  focus  of  these  several  volcanoes 
be  at  the  same  depth  below  the  surface,  a  great- 
er force  will  be  required  to  raise  the  molten 
masses  to  a  6  or  8  times  higher  level.  Whilst 
the  lowly  Stromboli  (Strongyle)  has  laboured 
restlessly,  at  least  since  the  times  of  the  Ho- 
meric traditions,  and  serves  as  a  light-house 
to  the  Tyrrhenian  Sea,  guiding  the  seaman  with 
its  fiery  signal  on  his  course,  the  more  lofty 
volcanoes  are  characterized  by  lengthened  pe- 
riods of  repose.  The  eruptions  of  the  greater 
number  of  the  colossal  volcanoes  that  crown 
the  Andes,  occur  at  intervals  almost  of  a  cen- 
tury apart :  where  exceptions  to  this  rule  have 
been  observed — and  I  long  ago  directed  atten- 
tion to  them — they  may  probably  be  connected 
with  the  circumstance,  that  the  communication 


between  the  volcanic  focus  and  the  crater  oi 
eruption  is  not,  cannot  be  conceived  to  be, 
equally  or  permanently  free  in  every  volcano 
at  all  times.  In  the  less  elevated  volcanoes 
the  channel  of  communication  may  be  closed 
for  a  season  ;  so  that  their  eruptions  become 
rarer,  without  their  being,  on  this  account,  any 
nearer  to  extinction. 

With  the  consideration  of  the  relation  be- 
tween the  absolute  heights  of  volcanoes  and 
the  frequency  of  their  activity,  in  so  far  as 
this  is  externally  visible,  the  place  at  which 
the  lava  flows  out  is  closely  connected.  Erup- 
tions from  the  crater  are  extremely  rare  in  the 
case  of  many  volcanoes  ;  they  generally  occur 
from  lateral  fissures  (as  noticed  by  the  celebra- 
ted historian,  Bembo,  in  the  16th  century,  whilst 
yet  a  youth),  at  places  where  the  flanks  of  the 
uplifted  mountain,  in  consequence  of  their  for- 
mation and  inclination,  offer  the  least  amount 
of  resistance(^^*).  Upon  these  fissures  cones 
of  eruption  are  occasionally  raised.  The  larger 
of  these  are  of  such  dimensions  that  they  are 
often  erroneously  designated  by  the  title  of  new 
volcanoes  ;  ranked  side  by  side,  they  show  the 
direction  of  a  fissure  which  has  again  become 
closed ;  the  smaller  ones  frequently  occur  in 
groups,  thickly  set  together,  and  cover  whole 
districts,  as  it  were  with  bell-shaped,  or  bee- 
hive like,  elevations.  To  the  latter  class  be- 
long the  hornitos  of  Jorullo(^^^),  and  the  cone  of 
eruption  of  Vesuvius  of  October,  1822,  of  the 
volcano  of  Awatscha,  according  to  Postels, 
and  of  the  lava  field  near  the  Baidare  mount- 
ains, in  the  peninsula  of  Kamtschatka,  accord- 
ing to  Erman. 

When  volcanoes  do  net  rise  free  and  isola- 
ted from  a  plain,  when,  on  the  contrary,  they 
are  surrounded  by  table-lands  from  9  to  12,000 
feet  high,  as  in  the  double  chain  of  the  Andes 
of  Quito,  this  circumstance  may  very  well  give 
rise  to  the  fact,  that  the  most  violent  eruptions, 
when  red-hot  ashes  and  scoriae  are  thrown  out 
with  detonations  that  are  heard  for  hundreds 
of  miles  around,  are  never  accompanied  with 
streams  of  lava<'^^*).  This  is  the  case  with 
the  volcanoes  of  Popayan,  of  the  lofty  plains  of 
Los  Pastes,  and  of  the  Andes  of  Quito ;  the 
single  volcano  of  Antesana,  among  the  latter, 
perhaps  excepted. 

The  height  of  the  cone  of  ashes,  and  the  di- 
mensions and  form  of  the  crater,  are  the  ele- 
ments in  the  figure  of  volcanoes  which  more 
particularly  impress  upon  each  of  them  an  in- 
dividual character;  but  both  of  these  elements, 
both  the  cone  and  the  crater,  are  perfectly  in- 
dependent of  the  magnitude  of  the  whole  mount- 
ain. Vesuvius  is  not  one-third  of  the  height  of 
the  Peake  of  Teneriffe,  yet  its  cone  of  ashes 
forms  one-third  of  the  whole  height  of  the 
mountain,  whilst  the  cone  of  the  Peake  is  only 
one  twenty-second  of  the  entire  elevation.  In 
the  case  of  another  volcano  of  much  greater 
height  than  the  Peake,  that  of  Rucu-Pichincha, 
namely,  the  relations  come  nearer  to  those  of 
Vesuvius.  Of  all  the  volcanoes  which  I  have 
seen  in  either  hemisphere,  Cotopaxi  is  that  of 
which  the  conical  form  is  the  most  regular  and 
beautiful.  A  sudden  melting  of  the  snow  of 
its  ashy  cone  indicates  the  proximity  of  an 
eruption.  Before  there  is  even  any  smoke 
visible  in  the  thin  strata  of  the  atmosphere 


70 


VOLCANOES. 


that  surround  the  summit  and  the  crater's 
mouth,  the  walls  of  the  ashy  cone  are  some- 
times heated  through,  when  the  entire  mount- 
ain presents  the  most  threatening  and  ill-omen- 
ed aspect  of  inky  black. 

The  crater  which,  except  in  very  rare  cases, 
occupies  the  summit  of  the  volcano,  forms  a 
cauldron-like,  and  often  accessible  valley,  whose 
bottom  is  subject  to  incessant  changes.     The 
greater  ar  less  depth  of  the  crater  is,  in  many 
volcanoes,  an  indication  of  the  proximity  or  re- 
moteness of  an  eruption.     In  the  cauldron-like 
crater  extensive  fissures  open  and  close  again 
alternately  ;  through  these  vapours  of  various 
kinds  find  vent,  or  small  rounded  fiery  throats, 
filled  with  molten  matters,  are  formed  upon 
them.     The  ground  rises  and  falls,  and  on  it 
are  piled  hillocks  of  ashes  and  cones  of  erup- 
tion, which  occasionally  rise  high  above  the 
edges  of  the  crater,  and  give  the  volcano  its 
characteristic  physiognomy  for  years ;  but  on 
the  occurrence  of  fresh  eruptions,  they  sink 
suddenly  down,  and  disappear.     The  openings 
of  these  cones  of  eruption,  which  rise  from  the 
floor  of  the  crater,  must  not,  as  is  too  frequent- 
ly done,  be  confounded  with  the  crater  itself, 
which  encircles  them.     When  the  crater  is  in- 
accessible, from  its  vast  depth,  and  the  perpen- 
dicular inward  slope  of  its  sides,  as  in  the  case 
of  Rucu-Pichincha  (14,946  feet  high),  one  can 
still  look  down  from  the  edges,  upon  the  sum- 
mits of  the  monticules  which  rise  within  the 
cauldron-like   crater,  partially  filled  with   sul- 
phureous vapours.  A  more  wonderful  or  grand- 
er natural  prospect  I  have  never  enjoyed.     In 
the  interval  between  two  eruptions,  the  crater 
of  a  volcano  may  exhibit  no  luminous   phe- 
nomenon, but  merely  open  fissures  and  jets  of 
watery  vapour ;  or  hillocks  of  ashes  that  can 
be  approached  without  danger,  are  found  upon 
its  scarcely  heated  bottom.   These  often  grati- 
fy the  wandering  geologist,  without  making 
him  run  any  risk,  by  casting  out  glowing  mass- 
es, which  fall  on  the  edges  of  the  cone  of  sco- 
riae, their  appearance  being  regularly  announ- 
ced by  slight,  and  entirely  local  shocks — earth- 
quakes on  a  small  scale.    Lava  occasionally 
flows  from  open  fissures,  or  small  fiery  gorges, 
into  the  crater  itself,  without  bursting  through 
its  walls,  or  overflowing  its  edges.     But  if  it 
does  break  through,  the  molten  spring  general- 
ly flows  smoothly,  and  in  such  a  determinate 
direction,  that  the  great  cauldron-like  valley, 
called  the  crater,  can  still  be  visited  during  the 
period  of  the  eruption.     Without  a  particular 
description  of  the  conformation,  and  also  of 
the  normal  structure   of  burning  mountains, 
phenomena  cannot   be  rightly  comprehended 
which  have  been  distorted  by  fantastical  de- 
scriptions, and  the  various   significations   at- 
tached to  the  words  crater,  volcano,  and  cone  ; 
or,  rather,  to  the  indefinite  and  indeterminate 
use  of  these  words.     The  edges  of  the  crater 
sometimes  show  themselves  much  less  liable 
to  change  than  might  be  expected.   A  compari- 
son of  De  Saussure's  measurements  with  my 
own,  yields  the  remarkable  result,  in  connection 
with  Vesuvius   at  least,  that  the  north-west 
edge  of  the  volcano,  the  Rocca  del  Palo,  may 
be  regarded  as  having  remained  for  forty-nine 
years  (1773-1822)  almost  without  change  in  its 


elevation  above  the  level  of  the  sea.    Any  dif- 1  and  two  men. 


ference  that  appears  may  be  looked  on  as  with 
in  the  possible  errors  of  measurement(*8'). 

Volcanoes  which  lift  their  summits  far  above 
the  limits  of  eternal  snow,  like  those  of  the 
Andes,  present  a  variety  of  peculiar  features. 
The  sudden  melting  of  the  snow  in  the  course 
of  an  eruption,  not  only  occasions  destructive 
floods,  torrents  in  which  heaps  of  smoking  ash- 
es are  floated  away  on  blocks  of  ice  ;  but  the 
accumulation  of  ice  and  snow  goes  on  produ- 
cing its  influence  uninterruptedly,  and  by  fil- 
tration into  the  trachytic  rocks,  even  whilst 
the  volcano  is  perfectly  quiescent.     Caverns 
are  thus  gradually  produced  on  the  declivities 
or  at  the  foot  of  the  burning  mountain,  and 
these  become  subterraneous  reservoirs  of  wa- 
ter, which  communicate  in  various  ways,  and 
by  narrow  mouths,  with  the  Alpine  rivulets  of 
Quito.     The  fishes   of  these  Alpine   streams 
multiply  greatly,  particularly  in  the  gloom  of 
the  caverns  ;  and  then,  when  the  earthquakes 
come,  which  precede  all  eruptions  of  volcanoes 
in  theAndes,  and  the  whole  mass  of  the  mount- 
ain  is  shaken,  the  subterraneous   caverns  at 
once  give  way,  and  pour  out  a  deluge  of  water, 
fishes,  and  tufaceous  mud.     This  is  the  singu- 
lar phenomenon  which  the  presence   of  the 
Pimelodes  Cyclopum(^'<'),  the  Prenadilla  of  the 
inhabitants  of  the  lofty  plains  of  Quito,  attests. 
When,  in  the  night  between  the  19th  and  20th 
of  June,  1698,  the  summit  of  Carguairazo,  a 
burning  mountain  18,000  feet  high,  crumbled 
together,  so  that  no  more  than  two  enormous 
rocky  horns  of  the  crater's  edge  remained,  the 
country  for  nearly  two  square  miles  was  deso- 
lated with   liquid  tuflf  and   argillaceous  mud 
(lodazales)  inclosing  dead  fishes.     So  also  was 
the  putrid  fever  of  the  mountain  town,  Ibarra, 
to  the  north  of  Quito,  which  occurred  seven 
years  before,  ascribed  to  an  eruption  of  fish 
from  the  volcano  Imbaburu. 

Water  and  mud  which,  in  the  volcanoes  of 
the  Andes,  do  not  pour  down  from  the  crater 
itself,  but  from  cavities  in  the  trachytic  mass 
of  the  mountain,  ought  not,  consequently,  in 
the  strict  sense  of  the  phrase,  to  be  reckoned 
among  the  number  of  proper  volcanic  phenom- 
ena. They  are  only  mediately  connected  with 
the  activity  of  volcanoes,  nearly  in  the  same 
measure  as  the  irregular  meteorological  pro- 
cess, which,  in  my  earlier  writings,  I  have  spo- 
ken of  under  the  title  of  the  Volcanic  storm. 
The  hot,  watery  vapour  which  rises  from  the 
crater,  and  mingles  with  the  atmosphere  during 
the  eruption,  forms  a  cloud  as  it  cools,  with 
which  the  column  of  ashes  and  fire,  many  thou- 
sand feet  in  height,  is  surrounded.  So  sudden 
a  condensation  of  vapour,  and  the  production 
of  a  cloud  of  enormous  superficial  dimensions, 
increase  the  electrical  tension,  as  Gay  Lussac 
has  shown.  Forked  lightnings  dart  from  the 
column  of  ashes,  and  the  rolling  thunder  of  the 
volcanic  storm  is  then  plainly  distinguishable 
from  the  rumbling  in  the  interior  of  the  mount- 
ain. This  was  well  observed  towards  the  end 
of  the  eruption  of  Vesuvius  in  the  month  of 
October,  1822.  The  lightning,  which  proceed- 
ed from  the  volcanic  steam-cloud  of  the  Katla- 
gia  burningrmountain  in  the  Island  of  Iceland, 
according  to  Olaffen's  account,  upon  one  occa- 
sion (17th  October,  1755),  killed  eleven  horses 


VOLCANOES. 


71 


Having  now,  in  our  physical  delineation,  por- 
trayed the  general  structure  and  dynamic  ac- 
tivity of  volcanoes,  we  have  still  to  cast  a 
glance  at  the  material  diversity  of  their  prod- 
ucts. The  subterraneous  forces  separate  old 
combinations  of  elements,  in  order  to  bring 
about  new  combinations  ;  they  farther,  and  at 
the  same  time,  put  the  matters  transformed  or 
changed  into  motion,  so  long  as  they  are  dis- 
solved by  heat  and  moveable.  The  solidifica- 
tion of  the  tenaciously  or  more  limpidly  fluid 
and  moveable  mass,  under  different  degrees  of 
pressure,  appears  to  be  the  principal  cause  de- 
termining diflferences  in  the  structure  of  Plu- 
tonic and  volcanic  rocks  or  mineral  species. 
The  mineral  mass  which  has  flowed  in  a  liquid 
state  from  a  volcanic  opening — a  molten  min- 
eral spring  —  is  called  lava.  Where  several 
streams  of  lava  have  encountered  and  several- 
ly restrained  each  other  in  their  course,  they 
spread  out  and  fill  extensive  basins,  where  they 
cool  into  stratified  beds.  These  few  points 
comprise  the  whole  of  the  general  features  in 
the  productive  activity  of  volcanoes. 

Minerals  which  merely  break  through  a  vol- 
cano often  remain  enclosed  in  the  products  of 
its  igneous  activity.  I  have,  for  instance,  seen 
angular  masses  of  syenite,  rich  in  felspar,  con- 
tained in  the  black  augitic  lava  of  the  Mexican 
volcano,  Jorullo  ;  but  the  masses  of  dolomite 
and  granular  limestone,  which  contain  beauti- 
ful druses  or  cavities  lined  with  crystallized 
minerals  —  vesuviane  and  garnets,  mejonite, 
nepheline,  and  sodalite — are  not  ejections  of 
Vesuvius :  "  they  rather  belong  to  a  very  ex- 
tensive formation,  tuff-strata,  older  than  the 
upheaval  of  Somma  and  Vesuvius,  and  are 
probably  products  of  submarine  volcanic  influ- 
ences, at  great  depths  below  the  surface"(^'^). 
Among  the  products  of  our  present  volcanoes 
there  are  five  metals  :  iron,  copper,  lead,  arse- 
nic, and  selenium,  discovered  by  Stromeyer  in 
the  crater  of  Volcano.  Through  the  smoking 
fumaroles,-  the  chlorides  of  iron,  copper,  lead, 
and  ammonium,  are  sublimed  ;  iron-glance(^"), 
and  common  salt  (the  latter  often  in  large  quan- 
tities), are  seen  filling  veins  in  recent  streams 
of  lava,  or  covering  fresh  fissures  of  the  cra- 
ter's edges. 

The  mineral  composition  of  lavas  differs  ac- 
cording to  the  nature  of  the  crystalline  rock  of 
which  the  volcano  consists  ;  according  to  the 
height  of  the  point  at  which  the  eruption  takes 
place — as  it  is  near  the  foot  of  the  mountain, 
or  in  the  vicinity  of  the  crater  ;  and  according 
to  the  temperature  of  the  interior.  Vitreous 
volcanic  products,  obsidian,  pearlstone,  or  pum- 
ice, are  entirely  wanting  in  some  volcanoes, 
and  in  others  are  only  ejected  from  the  crater 
itself,  or  from  some  considerably  elevated  point. 
These  important  and  complex  relations  can 
only  be  ascertained  by  careful  crystallographic 
and  chemical  researches.  My  companion  in 
my  Siberian  journey,  Gustavus  Rose,  and  after 
him,  Herman  Abich,  have  begun,  with  much 
acumen  and  success,  to  throw  clear  light  upon 
the  compact  texture  of  such  a  variety  of  vol- 
canic minerals. 

The  greater  portion  of  the  vapour  that  rises 
is  pure  steam  or  watery  vapour.  Condensed 
and  flowing  away  as  a  rivulet,  it  is  used  by  the 
goatherds  of  the  island  of  Pantellaria.    The 


stream  which  was  seen  flowing  from  a  latera 
fissure  in  the  crater  of  Vesuvius  on  the  morn- 
ing of  the  26th  of  October,  1822,  and  was  long 
regarded  as  hot  water,  was  found  by  Monticelli 
to  be  dry  ashes,  which  poured  forth  like  drift- 
sand  ;  it  was  lava  ground  to  dust  by  attrition. 
The  appearance  of  ashes,  however,  which  dark- 
en the  air  for  hours,  and  even  for  days,  and 
which,  by  adhering  to  the  leaves,  become  so 
destructive  to  vineyards  and  olive  trees,  in 
their  columnar  ascent,  borne  up  by  vapours, 
indicate  the  termination  of  every  great  erup- 
tion. This  is  the  magnificent  spectacle  which 
the  younger  Pliny  describes  in  the  celebrated 
letter  to  Cornelius  Tacitus,  and  which  he  com- 
pares, in  point  of  shape,  to  a  lofty-branched 
and  shady  pine  tree.  What  has  been  descri- 
bed as  flame  in  the  eruption  of  ashes,  is  cer- 
tainly not,  any  more  than  the  light  of  the  glow- 
ing red  cloud  that  floats  above  the  crater,  to 
be  ascribed  to  hydrogen  gas  on  fire.  It  is  rath- 
er the  reflection  of  light  from  the  upheaved 
molten  masses  ;  sometimes,  too,  it  may  be  the 
light  from  the  depths  of  the  fiery  gorge  cast 
upon  the  ascending  vapours  and  reflected  by 
them.  But  as  to  what  those  flames  may  be, 
which  have  been  occasionally  seen  ever  since 
Strabo's  time  during  the  activity  of  volcanoes 
on  the  coast,  and  that  have  risen  from  the  bo- 
som of  the  sea  immediately  before  the  uphea- 
val of  a  volcanic  island,  I  do  not  pretend  to  de- 
cide. 

If  we  are  asked  what  it  is  that  burns  in  vol- 
canoes, what  it  is  that  produces  the  heat  which 
melts  and  mixes  the  earths  and  metals,  and 
even  imparts  an  elevated  temperature,  for  ma- 
ny years,  to  streams  of  lava  of  great  thick- 
ness 1(^")  there  is  always  the  presumption 
that,  as  in  the  case  of  the  coal  fields  which 
catch  fire  and  go  on  burning,  volcanoes. must 
necessarily  be  connected  with  the  presence  of 
certain  substances  calculated  to  support  com- 
bustion. According  to  the  various  phases  of 
chemical  science,  we  have  had  bitumen,  iron 
pyrites,  the  moist  contact  of  finely  divided  sul- 
phur and  iron,  pyrophoric  substances,  and  the 
metals  of  the  alkalies  and  earths,  assigned  as 
the  cause  of  volcanic  phenomena  in  their  high- 
est intensity.  The  great  chemist  to  whom  we 
are  indebted  for  our  knowledge  of  the  most 
combustible  of  the  metallic  substances.  Sir 
Humphrey  Davy,  has  himself  renounced  his 
bold  chemical  hypothesis  in  the  last  volume 
he  published — "  Consolations  in  Travel,  and 
the  Last  Days  of  a  Philosopher" — a  work  that 
excites  painful  feelings  of  regret  in  the  mind 
of  the  reader.  The  great  mean  density  of  the 
earth  (5-44),  compared  with  the  specific  gravi- 
ty of  potassium  (0  865),  of  sodium  (0972),  and 
of  the  metals  of  the  earths  (12),  the  absence 
of  hydrogen  in  the  gaseous  emanations  of  the 
fissures  of  volcanoes,  and  the  streams  of  lava 
that  have  not  yet  cooled,  many  chemical  con- 
siderations, in  a  word,  rise  up  in  opposition  to 
the  earlier  conjectures  of  Davy  and  Ampere("*). 
Were  hydrogen  evolved  during  eruptions  of 
lava,  how  enormous  must  its  quantity  prove  in 
cases  where,  from  the  low  level  of  the  point 
whence  the  eruption  flows,  the  outpouring  mass 
spreads  over  many  square  miles  of  surface,  and, 
dammed  up  in  its  course,  acquires  a  thickness 
of  several  hundred  feet ;    as  happened  in  the 


72 


VOLCANOES. 


remarkable  eruption  at  the  foot  of  the  Skaptar- 
Jokul  in  Iceland  (11th  of  June  to  3d  of  August, 
1783),  which  has  been  described  by  Mackenzie 
and  Soemund  Magnussen.  The  same  difficul- 
ties present  themselves  in  connection  with  the 
small  quantities  of  azote  that  are  evolred, 
when  the  atmospheric  air  is  conceived  as  pen- 
etrating by  the  crater,  or,  as  such  an  act  has 
been  figuratively  expressed,  when  the  earth  is 
imagined  as  inspiring.  So  general,  so  deeply 
effective,  and,  in  reference  to  the  interior  of 
the  earth,  so  extensive  an  action  as  that  of 
volcanoes,  cannot  well  have  its  source  in  the 
chemical  affinities,  in  the  contact  of  individual 
and  only  locally  distributed  substances.  Mod- 
ern geognosy  prefers  seeking  for  this  source 
in  the  temperature  increasing  with  the  depth 
under  every  parallel  of  latitude,  in  the  great  in- 
ternal heat  of  the  globe,  which  is  due  to  its 
original  consolidation,  to  its  formation  in  space, 
to  the  spherical  contraction  of  vaporous  matter 
circulating  in  an  elliptical  orbit.  Beside  posi- 
tive knowledge,  stand  Conjecture  and  Opinion. 
A  philosophical  science  of  nature  strives  to  rise 
beyond  the  limited  requirements  of  a  bare  de- 
scription of  nature.  It  consists  not,  as  we 
have  several  times  reminded  the  reader,  in  the 
barren  accumulation  of  isolated  facts.  The  cu- 
rious, the  inquiring  spirit  of  man,  must  be  suf- 
fered to  make  excursions  from  the  present  into 
the  past,  still  to  surmise  what  cannot  be  posi- 
tively known,  and  to  revel  in  the  old,  and,  un- 
der various  shapes,  ever  recurring  myths  of  ge- 
ognosy. If  we  consider  volcanoes  as  irregular 
intermitting  springs,  which  pour  out  a  liquefied 
mixture  of  oxidized  metals,  alkalies  and  earths, 
that  flow  smoothly,  silently  enough,  once  the 
mixture,  uplifted  by  the  vast  force  of  com- 
pressed vapour,  finds  a  vent,  we  are  involunta- 
rily reminded  of  Plato's  geognostical  phanta- 
sies, according  to  which  hot  springs,  as  well 
as  all  the  varieties  of  volcanic  fiery  streams, 
are  effusions  of  Periphlegethon,  a  cause  uni- 
versally present  in  the  interior  of  the  globe(^95). 
Volcanoes,  in  their  mode  of  distribution  over 
the  surface  of  the  earth,  independently  of  all 
climatic  differences,  are  well  and  characteris- 
tically referred  to  two  classes,  viz.  :  Central 
volcanoes  and  Linear  volcanoes,  "  according 
as  a  central  and  common  point  of  eruption  for 
many  foci  all  around  is  established,  or  as  sev- 
eral vents  extending  in  one  direction,  and  at 
no  great  distance  from  each  other,  are  formed, 
along  the  course  apparently  of  a  lengthened 
fissure.  Linear  volcanoes,  again,  are  of  two 
kinds  :  they  either  rise  as  insulated  cones  from 
the  bottom  of  the  sea,  and  are  accompanied 
usually  on  one  side  by  a  primitive  mountain 
mass  running  in  the  same  direction,  the  foot 
of  which  they  seem  to  indicate  ;  or  they  stand 
upon  the  crest  of  the  mountain  chain,  and  form 
its  loftiest  summits"(i").  The  Peake  of  Ten- 
eriflfe,  for  example,  is  a  central  volcano,  the 
middle  point  of  the  volcanic  group  to  which 
the  outbreaks  of  Palma  and  Lancerote  belong. 
The  lengthened  chain  of  the  Andes,  which  runs 
like  a  wall  from  Southern  Chili  to  the  north- 
west coasts  of  America,  here  singly,  there  in 
two  and  three  parallel  lines,  connected  at  in- 
tervals by  narrow  transverse  yolks,  presents 
an  instance  upon  the  grandest  scale  of  the  oc- 
currence of  linear  volcanoes  on  dry  land.    The 


vicinity  of  active  volcanoes  in  the  line  o(  the 
Andes  is  proclaimed  by  the  sudden  appearance 
of  certain  species  of  rocks,  such  as  dolerite, 
melaphyre,  trachyte,  andesite,  and  dioritic  por- 
phyry, which  separate  the  so-called  primitive 
rocks,  as  well  as  the  schistose  and  sandstone 
transition  strata  and  the  tertiary  or  flcetz  for- 
mations. A  phenomenon  of  this  kind  constant- 
ly recurring,  begot  a  persuasion  in  my  mind  at 
an  early  period,  that  these  sporadic  rocks  had 
been  the  seat  of  volcanic  phenomena,  and 
had  been  determined  by  volcanic  eruptions. 
At  the  foot  of  the  great  Tunguragua,  near  Pe 
nipe,  on  the  banks  of  the  Rio  Puela,  I  for  the 
first  time,  and  distinctly,  saw  a  mica  schist, 
which  rested  upon  granite,  broken  through  by 
volcanic  rocks. 

The  linear  volcanoes  of  the  New  World, 
where  they  lie  near  to  one  another,  are  partial- 
ly in  a  state  of  reciprocal  dependance ;  it  i*9t-_ 
even  obvious  that  the  volcanic  activity  has  ^^ ^ 
been  gradually  advancing  for  centuries  in  par- 
ticular determinate  directions — in  the  Province 
of  Quito,  for  example,  from  north  to  south("^>. 
The  hearth  or  focus  itself  lies  under  the  whole 
of  the  elevated  lands  of  this  province  ;  the  par- 
ticular openings  by  which  communications  are 
established  with  the  atmosphere  constitute  the 
mountains  which  we  designate  by  special 
names,  such  as  Pichincha,  Cotopaxi  or  Tun- 
guragua, and  which,  by  their  grouping,  as  well 
as  by  their  height  and  form,  present  the  grand- 
est and  most  picturesque  prospect  that  is  any- 
where to  be  seen  within  a  small  compass  in  a 
volcanic  country.  As  the  outermost  members 
of  such  groups  of  linear  volcanoes  are  connect- 
ed with  one  another  by  subterraneous  commu- 
nications, as  multiplied  experience  shows,  this 
fact  reminds  us  of  Seneca's  old  and  truthful 
sentence(i^^),  "  that  the  burning  mountain  is 
but  the  passage  to  deeper-lying  volcanic  for- 
ces." In  the  Mexican  highlands,  likewise,  the 
volcanoes  (Orizaba,  Popocatepetl,  Jorullo,  Co- 
lima),  which  I  have  shown(^^')  all  to  lie  in  one 
direction,  between  18°  59'  and  19°  12'  N.  lati- 
tude, appear  to  indicate  a  transverse  fissure 
extending  from  sea  to  sea,  and  to  be  mutually 
dependant.  The  volcano  of  Jorullo  broke  out 
on  the  29th  of  September,  1759,  exactly  in  this 
direction,  upon  the  same  transverse  fissure, 
and  rose  to  a  height  of  1580  feet  above  the  sur- 
rounding level.  This  mountain  never  threw 
out  but  one  stream  of  lava  ;  precisely  like  Epo- 
meo  in  Ischia,  in  the  year  1302. 

But  if  Jorullo,  distant  as  it  is  some  German 
miles  from  every  active  volcano,  be,  in  the 
strictest  sense  of  the  word,  a  new  mountain, 
nevertheless  it  must  not  be  confounded  with 
the  appearance  of  the  Monte  Nuovo  near  Poz- 
zuolo  (19th  September,  1539),  which  is  to  be 
reckoned  among  the  number  of  upheavement 
craters.  I  have  already  said  that  it  were  more 
in  conformity  with  nature  to  assimilate  the 
eruption  of  the  newly  produced  Mexican  vol- 
cano with  the  upheaval  of  the  hill  of  Methone 
(now  Methana),  upon  the  peninsula  of  Traezene. 
This  upliftment,  described  by  Strabo  and  Pau- 
sanias,  has  led  one  of  the  most  imaginative  of 
the  Roman  poets  to  propound  views  which 
agree  in  a  very  remarkable  manner  with  those 
of  modern  geognosy :  "  A  tumulus  is  seen  at 
Traezene,  rugged,  and  without  wood  ;  once  a 


VOLCANOES. 


7  J 


level,  now  a  mountain ;  the  vapours  pent  up 
in  dark  caverns  sought  in  vain  for  a  crevice  of 
escape.  They  swelled  the  expanding  soil  un- 
der the  force  of  the  compressed  vapour,  like  a 
bladder  filled  with  air ;  it  swelled  like  the  skin 
of  a  two-horned  goat.  The  upheavement  re- 
mains upon  the  spot ;  the  high,  uplifted  hill  be- 
came hardened  in  the  course  of  time  into  a 
naked  rocky  mass."  So  picturesquely,  and, 
also,  as  analogous  appearances  lead  us  to  be- 
lieve, so  truly,  does  Ovid  describe  the  grand 
natural  incident  which  occurred  between  Trae- 
zene  and  Epidaurus,  282  years  before  the  com- 
mencement of  our  era,  and  therefore  45  years 
before  the  volcanic  separation  of  the  island  of 
Thera  (Santorin)  from  TherasiaC^o"). 

Of  all  the  islands  belonging  to  the  series  of 
linear  volcanoes,  Santorin  is  the  most  impor- 
tant. "  It  comprises  in  itself  the  entire  history 
of  upheaved  islands.  For  full  two  thousand 
years,  so  long  as  history  and  tradition  extend, 
Nature  has  not  ceased  from  her  attempts  to 
form  a  volcano  within  the  circuit  of  the  crater 
of  elevation"(^°^)-  Similar  insular  upheave- 
ments,  at  almost  regularly  recurring  intervals 
of  80  or  90  years,  are  exhibited  in  the  island  of 
St.  Michael,  one  of  the  group  of  the  Azores(""), 
though  here  the  bottom  of  the  sea  has  not  been 
uplifted  quite  at  corresponding  points.  The 
island  named  Sabrina  by  Captain  Tillard  unfor- 
tunately appeared  at  a  time  when  the  political 
state  of  the  maritime  nations  of  the  west  of 
Europe  was  little  favourable  to  scientific  inves- 
tigations (30th  Jan.,  1811);  so  that  this  great 
event  did  not  attract  the  same  degree  of  atten- 
tion as  was  bestowed  upon  the  island  of  Fer- 
dinandea,*  which  appeared  on  the  2d  of  July, 
1831,  but  soon  fell  to  pieces  again,  between  the 
limestone  coast  of  Sciacca  and  the  purely  vol- 
canic Pantellaria  in  the  Sicilian  Sea(=^''='). 

The  geographical  distribution  of  the  volca- 
noes which  have  continued  active  since  the 
historical  epoch,  their  frequent  situation  by  the 
sea-shore,  and  on  islands,  to  say  nothing  of  the 
recurrence,  from  time  to  time,  of  temporary 
eruptions  from  the  bottom  of  the  sea,  appears 
at  an  early  period  to  have  begotten  the  belief, 
that  volcanic  activity  was  connected  with  the 
vicinity  of  the  sea,  and  could  not  continue  with- 
out it.  "^tna  and  the  CEolian  isles,"  says 
Justin(='<'*),  or,  rather,  Trogus  Pompeius,  whom 
he  copies,  "  have  already  been  burning  for  many 
centuries  ;  and  how  were  this  long  continuance 
possible,  did  not  the  neighbouring  sea  supply 
food  for  the  firel"  To  explain  the  necessity 
for  the  neighbourhood  of  the  sea,  the  hypothe- 
sis of  the  penetration  of  sea- water  to  the  hearth 
of  the  volcano,  i.  e.,  to  the  deep-lying  strata  of 
the  earth,  has  in  recent  times  been  again  pro- 
posed. If  I  embrace  all  that  occurs  to  me,  de- 
rived either  from  personal  observation  or  from 
carefully  collected  facts,  it  seems  to  me  that 
everything  in  this  difficult  inquiry  depends  upon 
the  way  in  which  the  following  questions  are 
answered  :  Whether  the  undeniably  large  quan- 
tities of  watery  vapour,  which  volcanoes  emit, 
even  in  their  state  of  repose,  be  derived  from 
sea-water  loaded  with  salts,  or  from  sweet  at- 
mospheric water?      Whether,  with   different 


*  The  Graham  Island  of  English  geologists  ;  vide  Lyell's 
admirable  Principles  of  Geology,  vol.  ii.,  p.  266.  Sixth  edit., 
Lond.,  1840.— Te, 

K 


depths  of  the  volcanic  hearth  (a  depth,  for  ex- 
ample, of  88,000  feet,  at  which  the  expansive 
force  of  the  vapour  of  water  would  be  exerted 
under  a  pressure  of  2,800  atmospheres),  the  ex- 
pansive force  of  the  vapour  engendered  would 
be  competent  to  counterbalance  the  hydrostatic 
pressure  of  the  sea,  and  admit  the  access  of  its 
water  to  the  volcanic  hearth,  under  certain 
conditions  1(^''^)  Whether  the  many  metallic 
chlorides,  the  appearance,  indeed,  of  common 
salt  in  the  fissures  of  craters,  and  the  admix- 
ture of  hydrochloric  acid  vapours  with  the  wa- 
tery vapour  emitted,  lead  necessarily  to  the 
conclusion,  that  the  sea  must  have  access  to 
the  volcano  1  Whether  the  repose  of  the  vol- 
cano, be  this  temporary  only,  or  final  and  com- 
plete, depends  on  the  stoppage  of  the  channels 
which  previously  conducted  the  sea,  or  the  me- 
teoric water,  to  the  volcanic  hearth  1  Whether 
the  absence  of  flame  and  of  hydrogen  gas — for 
sulphuretted  hydrogen  belongs  to  the  solfataras 
rather  than  to  the  active  volcanoes — is  not 
rather  in  open  contradiction  with  the  assump- 
tion of  any  extensive  decomposition  of  water  1 
The  discussion  of  physical  questions  of  such 
importance  does  not  fall  within  the  scope  of  a 
Picture  of  Nature.  Here  we  attach  ourselves  to 
the  narration  of  phenomena ;  to  facts  in  the  geo- 
graphical distribution  of  yet  active  volcanoes. 
Now  facts  inform  us,  that  in  the  New  World, 
three  of  these — JoruUo,  Popocatepetl,  and  La 
Fragua — are  20,  33,  and  39  geographical  miles 
distant  from  the  sea-shores,  and  that  in  central 
Asia  (and  M.  Abel-Remusat("^)  first  directed 
the  attention  of  geologists  to  the  fact),  there  is  a 
great  volcanic  mountain  chain,  Thian-schan,  or 
the  Celestial  Mountains,  with  the  lava-emitting 
Pe-schan,  the  solfatara  of  Urumtsi,  and  the 
burning  mountain  of  Turfan  (Ho-tscheu),  the 
several  members  of  which  are  at  nearly  equal 
distances — 370  to  382  geographical  miles — from 
the  shores  of  the  Icy  Sea  and  of  the  Indian 
ocean.  The  distance  of  Pe-schan  from  the 
Caspian  Sea  is  also  full  340  geographical  miles  ; 
and  from  the  great  lakes,  Issikul  and  Balkasch, 
it  is  43  and  52  miles(=").  It  is  farther  remark- 
able, that  of  the  four  great  parallel  mountain 
chains — the  Altai,  the  Thian-schan,  the  Kuen- 
luen,  and  the  Himalaya,  which  cross  the  conti- 
nent of  Asia  from  east  to  west — it  is  not  the 
Himalaya,  or  the  chain  that  is  nearest  the 
ocean,  but  the  two  minor  chains,  the  Thian- 
schan  and  the  Kuen-luen,  at  the  distance  res- 
pectively of  400  and  180  geographical  miles 
from  the  sea,  that  are  found  vomiting  fire  like 
^Etna  and  Vesuvius,  and  producing  ammonia, 
like  the  volcanoes  of  Guatimala.  The  Chinese 
writers  describe,  in  unmistakable  terms,  streams 
of  lava,  10  Li  long,  as  occurring  in  the  eruptions 
of  flame  and  smoke  which  took  place  from  Pe- 
schan,  and  spread  far  and  wide,  in  the  1st  and 
7th  centuries  of  our  era.  *'  Burning  masses  of 
rock,"  say  they,  "  flowed  as  thin  as  melted  fat." 
These  few  compressed  facts,  which  have  not 
been  sufficiently  attended  to,  make  it  probable 
that  the  vicinity  of  the  sea,  and  the  access  of 
sea-water  to  the  burning  focus,  are  not  indis- 
pensably necessary  to  the  breaking  out  of  sub- 
terranean fires,  and  that  coasts  are  only  favour- 
able to  volcanic  eruptions,  because  they  form 
the  sides  or  edges  of  the  deep  sea-basin,  which, 
covered  with  strata  of  water,  offers  less  resist- 


74 


CLASSES  OF  ROCKS. 


ance,  and  lies  many  thousand  feet  lower,  than 
inland  and  more  lofty  countries. 

The  volcanoes  that  are  active  at  the  present 
time,  and  that  communicate  permanently  by 
craters  with  the  interior  of  the  earth  and  the 
atmosphere,  became  open  at  so  late  an  epoch, 
that  the  superior  cretaceous  deposits,  and  the 
whole  of  the  tertiary  formations,  were  already 
in  existence  when  they  arose.  This  is  pro- 
claimed by  the  trachytes,  and  also  by  the  basalts, 
which  frequently  form  the  walls  of  the  up- 
heavement  craters.  Melaphyres  extend  to  the 
middle  tertiary  strata  ;  but  have  already  begun 
to  show  themselves  under  the  Jura  formations, 
when  they  appear  breaking  through  the  varie- 
gated sandstone(*°8).  The  active  volcanoes  of 
the  present  time,  communicating  with  the  air 
by  craters,  must  not  be  conlounded  with  those 
older  eruptions  of  granite,  quartzose  porphyry, 
and  euphotide,  through  open,  but  speedily-clo- 
sed fissures  (forming  veins),  which  occur  in  the 
old  transition  strata. 

The  extinction  of  volcanic  activity  is  either 
partial  only,  so  that  the  subterranean  fire  finds 
another  vent  in  the  same  mountain  chain  ;  or 
it  is  total,  as  in  Auvergne  ;  later  examples  are 
supplied,  in  perfectly  historical  times,  by  the 
volcano  MosychlosC^"^),  on  the  island  dedicated 
to  Hephcestos,  whose  "  upward  flickering  fiery 
glow"  was  known  to  Sophocles,  and  by  the 
volcano  of  Medina,  which,  according  to  Burck- 
hardt,  threw  out  a  stream  of  lava  on  the  2d 
of  November,  1276.  Each  stage  of  the  volcan- 
ic activity,  from  its  first  excitement  to  its  ex- 
tinction, is  characterized  by  peculiar  products  : 
first,  by  fiery  scoriae,  by  trachytic,  pyroxenic, 
and  vitreous  lavas  in  streams,  by  scoriae  and 
tuff  ashes,  accompanied  by  the  evolution  of 
large  quantities  of  generally  pure  watery  va- 
pour ;  at  a  later  period  as  solfataras,  when 
there  is  an  evolution  of  watery  vapour  mixed 
with  sulphuretted  hydrogen  and  carbonic  acid 
gases  ;  lastly,  when  all  has  cooled,  by  exhala- 
tions of  carbonic  acid  gas  alone.  Whether  that 
singular  class  of  burning  mountains  which  dis- 
charge no  lava,  but  dreadful  devastating  streams 
of  hot  water(2'°),  loaded  with  burning  sulphur, 
and  rocks  ground  down  to  powder — such,  for 
instance,  as  Galunggung,  in  the  island  of  Java 
— present  us  with  what  may  be  called  a  normal 
condition,  or  only  a  certain  transitory  modifica- 
tion of  the  volcanic  process,  will  remain  a  ques- 
tion undecided,  until  they  have  been  visited  by 
geologists  possessed  at  the  same  time  of  a 
knowledge  of  modern  chemistry. 

Such  is  the  very  general  view  of  volcanoes, 
so  important  an  element  in  the  life  of  the  earth, 
which  I  have  here  endeavoured  to  throw  to- 
gether. It  is  based,  in  part,  upon  my  own  ob- 
servations ;  in  the  generality  and  comprehen- 
siveness of  its  outlines,  however,  upon  the  la- 
bours of  my  friend  of  many  years,  Leopold  von 
Buch,  the  greatest  geologist  of  our  age,  who 
was  the  first  to  recognize  the  intimate  connec- 
tion of  volcanic  phenomena,  and  their  mutual 
interdependence  in  regard  to  their  actions  alid 
their  relations  in  space. 

The  reaction  of  the  interior  of  a  planet  upon 
its  outer  crust  and  surface,  as  manifested  in 
the  phenomena  of  volcanoes,  was  long  consid- 
ered as  a  mere  isolated  phenomenon,  and  pe- 


culiar only  with  reference  to  the  destructive 
agency  of  its  dark  and  subterraneous  forces  ;  it 
is  but  very  lately,  and  greatly  to  the  advantage 
of  that  geology  which  is  founded  on  physical 
analogies,  that  the  volcanic  forces  have  begun 
to  be  regarded  as  formative  of  new  species  of 
rocks,  and  as  transformative  of  older  mineral 
masses.  Here,  indeed,  is  the  point  already  al- 
luded to,  where  a  more  deeply-grounded  doc- 
trine of  volcanoes  in  a  state  of  activity,  and  ei- 
ther casting  out  fire  or  vapour,  leads  us,  in  our 
general  Picture  of  Nature,  by  a  double  way, 
the  one  to  the  mineralogical  portion  of  geog- 
nosy, or  the  doctrine  of  the  structure  and  suc- 
cession of  the  strata  composing  the  crust  of  the 
earth  ;  the  other  to  the  form  and  fashion  of  the 
continents  and  groups  of  islands  raised  above 
the  level  of  the  sea,  or  the  doctrine  of  the  geo- 
graphical forms  and  outlines  of  the  several  por- 
tions of  the  earth.  Enlarged  views  of  such  an 
enchainment  of  phenomena  is  a  consequence 
of  the  philosophical  direction  which  the  serious 
study  of  geognosy  has  now  so  generally  taken. 
Greater  perfection  of  the  sciences  leads,  as  in 
the  political  improvement  of  mankind,  to  con- 
nection and  agreement,  where  there  had  for- 
merly been  separation  and  distinction. 

When  we  class  rocks  or  mineral  masses  not 
according  to  differences  in  the  form  and  ar- 
rangement of  their  constituent  particles,  into 
stratified  and  unstratified,  schistose  and  massy, 
normal  and  abnormal  rocks,  but  look  at  the 
phenomena  of  formation  and  transformation 
which  are  still  going  forward  under  our  eyes, 
we  discover  a  four-fold  process  of  production 
in  connection  with  rocks  :  1st.  Eruptive  rocks, 
rocks  thrown  out  from  the  interior  of  the  earth, 
in  a  liquefied,  or  softened  and  more  or  less  te- 
nacious state  (volcanic  and  Plutonic  rocks). 
2d.  Sedimentary  rocks,  rocks  deposited  from 
fluids  in  which  the  particles  had  been  either 
dissolved  or  suspended,  but  from  which  they 
were  precipitated  and  deposited  upon  the  sur- 
face of  the  crust  of  the  earth.  The  greater 
number  of  the  floetz  and  tertiary  groups.  3d. 
Metamorphic  rocks,  rocks  altered  in  their  inti- 
mate structure  and  stratification,  either  through 
the  contact  and  vicinity  of  a  Plutonic  or  vol- 
canic (endogenous)  C^^)  ejected  rock,  or — and 
this  is  more  commonly  the  case — altered  by  the 
penetration  of  the  vaporiform  subhmed  mat- 
ters(2i2),  which  accompany  the  escape  of  certain 
molten  ejected  masses.  4th.  Conglomerates 
— coarse  or  fine-grained  sandstones,  breccias — 
rocks  made  up  of  mechanically  divided  masses 
of  the  three  former  species. 

These  four-fold  rock-formations,  which  still 
go  on  at  the  present  day,  through  the  effusion 
of  volcanic  masses  in  the  shape  of  streams  of 
lava,  through  the  influence  of  these  masses 
upon  rocks  consolidated  at  a  former  period, 
through  mechanical  separation  or  chemical  pre- 
cipitation from  liquids  charged  with  carbonic 
acid,  finally,  through  the  cementation  of  frag- 
ments often  of  totally  different  kinds  of  rocks, 
are  phenomena  and  formative  processes  which 
can,  however,  only  be  regarded  as  weak  reflec- 
tions of  what  went  on  under  the  higher  inten- 
sity of  action  in  the  life  of  the  earth  during  the 
chaotic  state  of  the  primitive  world,  and  under 
totally  diflferent  conditions  of  pressure  and  high 
temperature,  not  only  of  the  wliQle  crust  of  the 


•^ 


FUNDAMENTAL  FORMS  OF  ROCKS. 


78 


earth,  but  of  the  atmosphere,  surcharged  with 
moisture  and  of  much  greater  extent  than  it  is 
at  the  present  day.  If  at  the  present  time,  on 
surfaces  as  extensive  as  Europe,  we  scarcely 
find  four  openings  (volcanoes)  through  which 
eruptions  of  fire  and  molten  matters  can  take 
place,  the  firm  crust  of  the  earth  was  traversed 
in  former  periods  by  vast  open  fissures,  through 
which  mountain  chains  were  upheaved,  or  into 
which  streams  of  molten  rock — granite,  por* 
phyry,  basalt,  and  melaphyre — were  injected, 
and  by  which  they  were  variously  stopped  and 
filled  up.  At  former  epochs,  in  the  much  and 
variously  fissured,  thinner,  and  upwardly  and 
downwardly  fluctuating  crust  of  the  earth,  there 
were  almost  everywhere  passages  of  commu- 
nication between  the  molten  interior  and  the 
atmosphere.  Gaseous  emanations  arising  from 
very  dissimilar  depths,  and  therefore  bringing 
chemically  different  substances,  then  animated 
the  Plutonic  formative  and  transformative  pro- 
cesses. The  sedimentary  formations,  too,  the 
precipitations  from  liquids,  which  we  designate 
travertin,  and  which  we  see  proceeding  in  the 
neighbourhood  of  Rome  as  well  as  of  Hobart 
Town  in  Australia,  from  cold  and  hot  springs 
and  river  waters,  give  but  a  very  poor  idea  of 
the  origination  of  the  floetz  formations.  Our 
seas,  in  virtue  of  processes  which  have  not  yet 
been  examined  generally  enough,  or  with  suffi- 
cient care,  gradually  form  by  precipitation,  by 
overflowing  and  by  cementation,  small  calca- 
reous banks,  which,  at  some  points,  almost  ap- 
proach Carrara  marble  in  hardness("3).  This 
process  goes  on  upon  the  Sicilian  coasts,  the 
Island  of  Ascension,  and  King  George's  Sound 
in  Australia.  On  the  coasts  of  some  of  the 
"West  India  islands  these  formations  of  the 
present  ocean  now  enclose  earthenware  ves- 
sels and  other  products  of  human  manufactu- 
ring industry ;  and  in  the  Island  of  Guadaloupe, 
even  skeletons  of  the  Carib  race  of  men.  The 
negroes  of  the  French  colonies  characterize 
this  formation  as  the  "  Masonry  of  God"  (Ma- 
(jonne-bon-Dieu)  ("*).  In  the  Island  of  Lan- 
cerote,  one  of  the  Canaries,  there  is  a  small 
oolitic  stratum,  admitted  to  be  a  product  of  the 
sea  and  of  storms,  but  which,  despite  its  new- 
ness, reminds  us  of  the  Jurassic  limestone(2^^). 

The  compound  rocks  are  determinate  asso- 
ciations of  certain  simple  minerals — felspar, 
mica,  solid  silicic  acid,  augite,  and  nephehne. 
Very  similar  rocks,  i.  e.  rocks  made  up  of  the 
same  elements  but  otherwise  grouped,  are  pro- 
duced by  volcanic  processes  under  our  eyes,  at 
the  present  time,  just  as  they  were  in  former 
epochs  of  the  world's  history.  The  independ- 
ence of  rocks  in  respect  of  geographical  posi- 
tion or  relationship,  is  so  great,  that,  as  we 
have  already  observed("^),  the  geologist  sees 
with  amazement,  to  the  north  and  south  of  the 
equator,  in  the  farthest  zones  of  the  earth,  the 
same  familiar  appearances  in  the  rocks,  the 
repetition  of  the  minutest  details  in  the  pe- 
riodic series  of  the  Silurian  strata,  and  in  the 
eflfects  of  contact  with  augitic  masses,  the  prod- 
ucts of  eruptions. 

If  we  now  take  a  closer  view  of  the  four  fun- 
damental forms  of  rock  (the  four  phases  in  the 
formative  process)  in  which  the  stratified  and  un- 
stratified  portions  of  the  crust  of  the  earth  pre- 
sent themselves  to  us,  we  may  designate  among 


the  endogenous  or  eruptive  rocks,  (the  massive 
and  abnormal  rocks  of  some  modern  geologists), 
the  following  principal  groups,  as  immediate 
evidences  of  subterraneous  activity,  viz. : 

Granite  and  Syenite — of  very  different  rel- 
ative ages,  but  frequently  penetrating  both  gran- 
ite and  syenite  of  more  recent  formation  in 
veins(2i7).  Along  with  these  it  is  also  proper 
to  consider  the  forcing  or  upheaving  power. 
"Where  granite  protrudes  in  evenly  vaulted 
ellipsoids,  in  great  masses,  like  islands,  wheth- 
er this  be  in  the  Harzforest,  or  in  Mysore,  or 
in  Lower  Peru,  it  is  always  covered  with  layers 
that  have  become  fissured  into  blocks.  Suoh 
a  rocky  sea  probably  owes  its  origin  to  a  con- 
traction of  the  upper  surface  of  the  granitic 
vault,  which,  on  its  protrusion,  and  originally, 
must  have  been  very  much  expanded"("^'»). 
In  Northern  Asia  also(=*^^),  in  the  charming, 
the  romantic  neighbourhood  of  Lake  Kolyvan, 
on  the  north-western  declivity  of  the  Altai 
range,  as  also  on  the  slopes  of  the  maritime 
chain  of  Caraccas,  near  Las  Trincheras(2='°),  I 
observed  the  granite  subdivided  into  blocks  or 
pilesj  in  consequence,  possibly,  of  such  con- 
tractions, but  which  in  these  cases  appear  to 
have  extended  deeply  into  the  interior.  Far- 
ther to  the  south  of  Lake  Kolyvan,  towards  the 
confines  of  the  Chinese  province  Hi,  between 
Buchtarminsk  and  the  river  Narym,  the  char- 
acters of  the  entire  mass  of  ejected  rock,  which 
is  here  unaccompanied  by  gneiss,  are  more  stri- 
king than  I  have  observed  them  in  any  other 
part  of  the  globe.  The  granite,  always  scaling 
and  crumbling  on  the  surface,  and  splitting  up 
into  tabular  masses,  rises  in  the  steppes  here 
in  low  semi-globular  hillocks,  not  more  than  six 
or  eight  feet  high,  there  in  basalt-like  knolls, 
which  run  out  at  opposite  sides,  as  it  were, 
into  thin  wall-like  effusions(=*='i).  By  the  cat- 
aracts of  the  Orinoco,  as  well  as  in  the  Fichtel- 
gebirge  (Seissen),  in  Gallicia,  and  betwixt  the 
Southern  Ocean  and  the  lofty  platforms  of  Mex- 
ico (at  Papagallo),  I  have  seen  granite  in  great 
depressed  globular  masses,  which,  like  basalt, 
split  or  scaled  off  in  concentric  layers.  In  the 
valley  of  the  Irtisch,  between  Buchtarminsk 
and  Ustkamenogorsk,  the  granite  covers  the 
clay-slate  for  a  mile  in  length("2)^  and  pene- 
trates the  same  strata  from  above  in  slender 
veins,  which  are  numerously  branched,  and 
wedge-shaped  at  their  extremities.  I  have  ad- 
duced these  particulars  by  way  of  examples, 
only  that  I  may  illustrate  the  individual  char- 
acters of  an  eruptive  rock  in  one  of  the  most 
widely  diffused  of  the  mineral  masses.  In  the 
same  way  as  the  granite  overlies  the  schists  in 
Siberia,  and  in  the  Department  of  Finisterre 
(Isle  de  Michau),  so  does  it  cover  the  Jurassic 
limestone  in  the  mountains  of  Oisons  (Fer- 
ments), and  syenite,  and  chalk  with  syenite  in- 
terposed, near  Weinbohla,  in  Saxony(='").  In 
the  Ural  mountains  near  Mursinsk,  the  granite 
shows  drusy  cavities,  and  the  druses  here,  like 
the  fissures  and  druses  of  newer  volcanic  pro- 
ductions, are  the  Plutonic  seat  of  numerous 
beautiful  cystals,  particularly  of  beryl  and  topaz. 

QuARTzosE  Porphyry,  from  its  relations  of 
stratification,  having  frequently  the  character 
of  veins.  The  base  is  generally  a  finely  gran- 
ular mixture  of  the  same  elements  which  pre- 


76 


FUNDAMENTAL  FORMS  OF  ROCKS. 


sent  themselves  to  us  as  large  embedded  crys- 
tals. In  granitic  porphyry,  which  is  very  poor 
in  quartz,  the  felspathic  base  is  at  once  granu- 
lar and  foliaceous^*^'*). 

Greenstone  or  Diorite — granular  mixtures 
of  white  albite  and  blackish-green  hornblende, 
constituting  dioritic  porphyry,  when  a  base  of 
denser  texture  is  present  in  which  the  crystals 
lie  embedded  distinctly.  These  greenstones, 
which,  pure  in  one  place,  pass  in  another  into 
serpentine,  from  the  laminae  of  diallage  which 
they  include  (Fichtelgebirge),  are  occasionally 
found  lying  in  beds  upon  the  old  stratification 
clefts  of  the  green  clay  slate,  and  penetrating 
them;  but  they  more  frequently  make  their 
way  through  the  rock  in  the  manner  of  veins, 
or  they  present  themselves  as  greenstone  balls, 
analogous  in  all  respects  to  balls  of  basalt  and 
porphyryC^^**). 

HypERSTHENE  RocK — a  granular  mixture  of 
Labrador  felspar  and  hypersthene. 

EuPHOTiDE  and  Serpentine,  occasionally  con- 
taining crystals  of  augite  and  uralite,  instead  of 
diallage,  and  thus  nearly  allied  to  a  more  com- 
mon rock,  and,  I  might  add,  one  that  indicates 
a  still  higher  degree  of  eruptive  activity,'  viz., 
augitic  porphyry(=^26^ 

Melaphyre,  Augitic,  Uralitic,  and  Oligo- 
GLAssic  Porphyry.  To  the  last  belongs  the  true 
verd  antique,  so  celebrated  as  a  material  em- 
ployed in  the  arts. 

Basalt,  with  olivine  and  constituents  becom- 
ing gelatinous  with  acids,  phonolite  (porphy- 
ritic  slate),  trachyte  and  dolerite.  The  sec- 
ond of  these  rocks  always  divides  into  thin  ta- 
bles ;  the  first  only  shows  this  structure  par- 
tially, which,  however,  gives  them  both  an  ap- 
pearance of  stratification  over  extensive  dis- 
tricts. According  to  Girard,mesotype  and  neph- 
eline  form  important  elements  in  the  composi- 
tion and  intimate  texture  of  basalt.  The  neph- 
eline  of  basalt  reminds  the  geologist  of  the  mi- 
ascite  of  the  Ilmengebirge  in  the  Ural  chainC^'^^), 
which  frequently  replaces  granite,  and  occasion- 
ally contains  zircon,  as  well  as  of  the  pyroxenic 
nepheline  discovered  by  Gumprecht  near  Lobau 
and  Chemnitz. 

To  the  second  class  of  fundamental  forms, 
the  sedimentary  rocks,  belongs  the  greater 
portion  of  the  formations  which  used  to  be  ar- 
ranged under  the  old  systematic,  but  by  no 
means  correct,  designation  of  Transition  and 
Floetz,  or  secondary  and  tertiary  formations. 
Had  the  igneous  rocks  exerted  nothing  of  an 
uplifting,  and,  with  simultaneous  quaking  of  the 
earth,  of  a  concussive  influence  upon  these 
sedimentary  formations,  the  surface  of  our 
planet  would  have  consisted  of  a  series  of  uni- 
form strata  horizontally  disposed  one  upon  an- 
other. Without  mountains,  on  whose  acclivi- 
ties the  progressive  diminution  in  the  tempera- 
ture of  the  air  is  picturesquely  reflected,  not 
only  in  the  luxuriance  of  vegetation,  but  in  the 
kinds  of  plants  that  are  produced,  the  monot- 
onous surface  would  only  have  been  broken 
here  and  there  by  ravines  eroded  by  water- 
courses or  by  small  collections  of  drift,  the  ef- 
fect of  masses  of  fresh  water  thrown  into  gen- 
tle undulations  ;  the  several  continents  from 
pole  to  pole,  and  under  every  variety  of  cli- 
mate, would  have  presented  the  dreary  uni- 


formity of  the  South  American  Llanos  or  of  the 
Northern  Asiatic  steppes.  As  in  the  greater 
portion  of  these,  we  should  then  have  seen  the 
vault  of  heaven  resting  on  the  plain,  and  the 
stars  rising  and  setting  as  if  they  emerged 
from  the  bosom  of  the  ocean,  and  dipped  into  it 
again.  But  such  a  state  of  things  even  in  the 
primitive  world  could  never  have  been  of  any 
considerable  duration  as  regards  time,  nor  of 
any  thing  like  general  prevalence  in  respect  of 
space  ;  the  subterraneous  powers,  at  every 
epoch  in  the  history  of  nature,  have  been  at 
work  striving  to  subvert  and  to  change  it. 

Sedimentary  strata  are  precipitated  or  de- 
posited from  liquids,  according  as  the  matter 
before  the  formation  was  either  held  chemical- 
ly dissolved,  as  in  the  case  of  lime,  or  merely 
I  suspended  and  mixed,  as  in  the  case  of  clay- 
I  slate,  mica-slate,  &c.  But  even  when  earthy 
I  matters  are  thrown  down  from  fluids  impreg- 
i  nated  with  carbonic  acid,  the  descent  of  the 
matter  during  its  precipitation  and  accumula- 
tion into  strata,  must  be  regarded  as  a  me- 
chanical element  in  the  process  of  formation. 
This  view  is  of  some  importance  in  connection 
with  the  envelopment  of  organic  bodies  in  pet- 
rifying calcareous  tufl^s.  The  oldest  sediments 
of  the  transition  and  secondary  formations 
have  apparently  taken  place  from  waters  more 
or  less  elevated  in  temperature,  and  at  a  pe- 
riod when  the  heat  of  the  upper  crust  of  the 
earth  was  still  very  considerable.  In  this  way, 
therefore,  a  Plutonic  influence  was  also  at  work 
to  a  certain  extent  in  connection  with  the  sedi- 
mentary strata,  particularly  the  oldest  of  them  ; 
these  strata,  however,  appear  to  have  become 
hardened  from  the  state  of  mud  into  the  schis- 
tose structure,  under  great  pressure  ;  not  like 
the  rocks  that  have  risen  up  from  the  interior 
(granite,  porphyry,  basalt),  to  have  been  con- 
solidated by  cooling.  As  the  primitive  waters 
of  the  globe  cooled  by  degrees,  they  became 
capable  of  holding  a  larger  and  larger  quantity 
of  carbonic  acid  gas  in  solution,  which  they 
may  have  attracted  from  the  atmosphere,  sur- 
charged with  this  gas  in  the  earlier  epochs  of 
creation,  and  so  of  holding  dissolved  a  larger, 
quantity  of  calcareous  earth. 

The  Sedimentary  strata,  from  which  we 
here  separate  all  the  other  exogenous  purely 
mechanical  precipitates  of  sand  or  fragmentary 
rocks,  are  these  ; 

Schists  or  Slates  of  the  inferior  and  supe- 
rior transition  rocks,  consisting  of  the  Silurian 
and  Devonian  formations  ;  from  the  lower  Si- 
lurian, or  as  they  were  once  designated,  Cam- 
brian, strata,  to  the  uppermost  bed  of  the  Old 
red  sandstone  or  Devonian  formation,  where  it 
comes  in  contact  with  the  Mountain  limestone  ; 

Carboniferous  deposits — Coal  formation  ; 
.  Limestones,  interstratified  in  the  transition 
and  coal  formations  ;  Zechstein,  Muschelkalk, 
Jura  formation  and  Chalk,  also  the  portion  of 
the  tertiary  formation  which  does  not  present 
itself  to  us  as  sandstone  and  conglomerate  ; 

Travertine,  fresh-water  limestone,  the  si- 
licious  sinter  of  hot  springs — formations. that 
have  originated  not  under  the  pressure  of  great 
pelagic  coverings  of  water,  but  almost  in  con- 
tact with  the  air  in  shallow  pools  and  rivulets ; 

Infusorial  strata,  a  geological  phenome- 


METAMORPHOSES  OF  ROCKS. 


77 


non,  the  vast  significance  of  which,  as  proclaim- 
ing the  influence  of  organic  activity  upon  the 
formation  of  the  solid  constituents  of  the  earth, 
was  discovered  in  very  recent  times,  by  my  in- 
lellectually-gifted  friend  and  fellow-traveller, 
Ehrenberg. 

If  in  this  short  but  comprehensive  survey  of 
the  mineral  constituents  of  the  crust  of  the 
earth,  we  do  not  immediately  refer  to  numbers 
of  simple  sedimentary  rocks,  the  various  con- 
glomerate and  sandstone  formations,  partly  de- 
posited from  liquids,  that  are  so  variously  in- 
termingled with  the  schists  and  the  limestones 
both  of  the  floetz  and  transition  series,  this  is 
only  because  these,  besides  fragments  of  erup- 
ted and  sedimentary  rocks,  also  contain  pieces 
of  gneiss,  mica-schist,  and  other  metamorphic 
masses.  The  obscure  process  of  transforma- 
tion (metamorphosis),  and  the  influence  it  ex- 
erts, must,  from  this  showing,  constitute  the 
third  class  of  fundamental  forms. 

The  endogenous  or  eruptive  rocks  (granite, 
porphyry,  and  melaphyre),  exert  an  influence, 
as  already  oftener  than  once  observed,  not 
merely  of  a  dynamical  kind,  shattering  or  up- 
heaving, erecting  or  pushing  strata  aside ;  by 
their  presence  they  farther  produce  changes  in 
the  chemical  composition  of  their  constituents, 
as  well  as  in  the  nature  of  their  intimate  tex- 
ture. NeAr  species  of  rocks  are  produced, 
gneiss  and  mica  slate,  and  granular  or  sac- 
charoidal  limestone  (Carrara  and  Parian  mar- 
ble). The  old  Silurian  or  Devonian  transition 
schists,  the  belemnitic  limestone  of  Tarantaise, 
the  grey  unlustrous  macigno  or  cretaceous 
sandstone  of  the  Northern  Apennines,  with  its 
included  sea-weed,  are  difficult  of  recognition 
after  their  transformation  into  new  and  fre- 
quently-sparkling textures.  The  belief  in  the 
metamorphosis,  indeed,  has  only  been  confirm- 
ed since  we  have  succeeded  in  following  the 
several  phases  of  the  transformation,  step  by 
step,  and  have  come  to  the  assistance  of  in- 
ductive conclusions  with  the  results  of  direct 
chemical  experiments,  the  employment  of  dif- 
ferent fusing  heats,  degrees  of  pressure,  and 
rates  of  cooling.  When  the  study  of  chemical 
combinations  is  extended  under  the  guidance 
of  leading  ideas("8),  we  find  that  from  the  nar- 
row confines  of  our  laboratories,  we  can  dif- 
fuse a  clear  light  over  the  wide  field  of  geolo- 
gy, over  the  great  subterraneous  rock-compo- 
sing and  rock-transforming  workshop  of  Na- 
ture. The  philosophical  inquirer  escapes  being 
deceived  by  seeming  analogies,  by  limited  views 
of  the  natural  processes,  when  he  keeps  steadi- 
ly in  his  eye  the  complication  of  circumstan- 
ces which,  in  the  intensity,  the  immeasurable- 
ness  of  their  force,  were  competent,  in  the 
primitive  world,  to  modify  the  reciprocal  influ- 
ences of  individual  substances  familiarly  known 
to  us  at  the  present  day.  The  simple  or  unde- 
composed  bodies  have  unquestionably  obeyed 
the  same  forces  of  affinity  at  all  times ;  and 
where  contradictions  seem  to  meet  us  now,  it 
is  my  most  intimate  persuasion,  that  chemistry 
will  herself,  for  the  most  part,  come  upon  the 
traces  of  conditions  not  fulfilled  in  like  or  due 
measure,  as  causes  of  these  contradictions. 

Accurate  observations,  embracing  extensive 
districts  of  mountainous  country,  satisfy  us  that 


the  eruptive  rocks  do  not  intei  vene  as  any  dig- 
orderly  or  lawless  power.  In  the  most  distant 
countries  of  the  world,  we  frequently  see  gran- 
ite, basalt,  or  diorile,  exerting  their  transform- 
ative force,  in  every  the  most  minute  particu- 
lar, alike  upon  strata  of  clay-slate,  on  thick 
beds  of  limestone,  and  on  the  grains  of  quartz 
of  which  sandstone  consists.  As  the  same 
kind  of  endogenous  rock  almost  everywhere 
exerts  the  same  kind  of  influence,  different 
kinds  of  rocks  belonging  to  the  same  class  ol 
endogenous  or  eruptive  formations,  exhibit,  on 
the  contrary,  very  different  characters.  In- 
tense heat,  above  all,  has  exerted  an  influence 
in  the  whole  of  the  phenomena  ;  but  the  degree 
of  molten  fluidity  attained — perfect  mobility  of 
particles,  or  a  more  viscid  or  glutinous  adhesion 
among  them — has  been  very  different  in  gran- 
ite and  basalt ;  in  different  geological  epochs, 
indeed  (phases  in  the  transformation  of  the  crust 
of  the  earth),  along  with  the  eruptions  of  gran- 
ite, basalt,  porphyritic  greenstone  or  serpentine, 
various  other  substances  dissolved  in  vapours 
have  arisen  from  the  interior  laid  open.  And 
this  is  the  place  to  remind  the  reader  anew, 
that  in  the  rational  views  of  modern  geology, 
the  metamorphosis  of  rocks  is  not  limited  to  the 
mere  phenomena  of  contact,  to  the  apposition 
of  two  different  kinds  of  rock  ;  but  that  geneti- 
cally it  comprises  all  that  has  accompanied  the 
protrusion  of  a  particular  ejected  mass.  In 
situations  where  no  immediate  contact  has 
taken  place,  the  mere  vicinity  of  such  a  mass 
causes  modifications  in  the  induration,  the  sil- 
icification,  the  granulation,  the  crystallization 
of  adjacent  rocks. 

All  eruptive  rocks  penetrate  the  sedimentary 
strata,  and  other  likewise  endogenous  masses, 
as  veins  ;  but  the  distinction  that  is  apparent 
between  the  Plutonic  rocks(2^') — granite,  por- 
phyry, serpentine — and  those  which,  in  a  more 
restricted  sense,  are  called  volcanic  (trachyte, 
basalt,  lava),  is  of  especial  importance.  The 
rocks  which  our  present  volcanoes,  as  rem- 
nants of  the  activity  of  the  body  of  the  earth, 
produce,  appear  in  narrow  streams,  which, 
however,  may  still  form  sufficiently  wide  beds 
when  several  of  them  meet  in  hollows  or  ba- 
sins. Basaltic  eruptions,  where  they  have  been 
traced  deeply,  have  been  repeatedly  seen  to 
terminate  in  slender  taps.  Flowing  from  nar- 
row openings,  as  in  the  Pftasterkaute,  near 
Marksuhl,  two  miles  from  Eisenach,  in  the  blue 
knolls,  near  Eschwega  (banks  of  the  Werra), 
and  at  the  Druid's-stone,  on  the  Hollert  ridge 
(Siegen),  to  cite  three  examples  indigenous  to 
Germany,  the  basalt  breaks  through  the  red 
sand-stone  and  greywacke  schist,  and  spreads 
out  above,  like  the  cap  of  a  mushroom,  into 
knolls,  which  in  one  place  appear  split  into 
columnar  groups,  in  another  are  thinly  strati- 
fied. Not  so  granite,  syenite,  quartzose,  por- 
phyry, serpentine,  and  the  entire  series  of  un- 
stratified  massy  rocks,  which,  from  an  attach- 
ment to  mythological  nomenclature,  have  been 
called  Plutonic.  These,  with  the  exception  of 
a  few  veins,  have  been  ejected,  not  in  a  molten 
liquefied  state,  but  in  one  merely  tenacious  and 
softened,  and  not  from  narrow  crevices,  but 
from  wide  valley-like  chasms,  and  extensive 
gorges.  They  have  been  forced,  they  have  not 
flowed  out :  they  present  themselves  not  in 


78 


METAMORPHOSES  OF  ROCKS. 


streams,  like  lava,  but  spread  out  in  immense 
massesC").  Among  the  dolerites  and  tra- 
chytes, some  groups  give  indications  of  a  cer- 
tain basalt-like  fluidity  ;  others,  expanded  into 
vast  bell -shaped  elevations  and  craterless 
domes,  appear  to  have  been  merely  softened 
when  they  were  protruded.  Other  trachytes, 
again,  those  of  the  Andes  among  the  number, 
which  I  frequently  found  very  closely  allied  to 
the  greenstones  and  syenitic-porphyries,  so  rich 
in  silver,  and  then  without  quartz,  lie  in  beds 
like  granite  and  quartzose- porphyry. 

Experiments  upon  the  alterations  which  the 
structure  and  chemical  constitution  of  rocks 
undergo  through  fire("^),  have  showed  that  the 
volcanic  masses,  diorite,  augitic  porphyry,  ba- 
salt, and  lava  from  JEtna,  according  to  the  de- 
gree of  pressure  under  which  they  were  melted, 
and  the  rate  of  their  cooling,  were  either,  when 
quickly  cooled,  brought  to  the  state  of  a  black 
glass  of  an  even  fracture,  or  when  slowly  cool- 
ed made  to  assume  the  appearance  of  a  stony 
mass  having  a  granular  crystalline  texture. 
The  crystals  in  such  cases  were  either  pro- 
duced on  the  sides  and  cavities,  or  embedded 
in  the  general  basic  mass.  The  same  material 
— and  this  consideration  is  of  great  importance 
as  regards  the  nature  of  the  eruptive  rock,  or 
the  transformations  it  has  undergone — yields 
the  most  dissimilar-looking  products.  Carbo- 
nate of  lime,  melted  under  high  pressure,  does 
not  lose  its  charge  of  carbonic  acid  ;  the  cooled 
mass  is  granular  limestone,  saccharoidal  mar- 
ble. So  much  for  crystallization  in  the  dry 
way  ;  in  the  moist  way,  calcareous  spar  as  well 
as  Aragonite  is  produced,  the  former  under  a 
moderate,  the  latter  under  a  higher,  degree  of 
heatC^").  According  to  diversities  of  temper- 
ature, the  consolidating  particles  of  crystals  in 
process  of  formation  arrange  themselves  va- 
riously and  in  particular  determinate  direc- 
tions ;  the  very  form  of  the  crystals,  indeed, 
varies  with  the  temperature  under  the  influ- 
ence of  which  they  are  producedC^").  There 
is,  moreover,  under  certain  relations,  and  with- 
out the  intervention  of  any  fluid  state,  a  trans- 
position(2^*)  of  the  minute  particles  of  a  body, 
which  is  proclaimed  by  optical  effects.  The 
phenomena  presented  by  devitrifaction,  by  the 
production  of  cemented  and  cast  steel,  by  the 
transition  of  the  fibrous  structure  of  iron  into 
one  that  is  granular,  under  the  influence  of  el- 
evated temperature(22^),  perhaps  even  of  very 
insignificant  but  equable  and  long-continued 
concussions,  all  conduce  to  throw  light  upon 
the  processes  of  geological  metamorphosis. 
Heat  can  even  induce  opposite  effects  at  the 
same  time  upon  crystalline  bodies ;  for  Mits- 
cherlich's  beautiful  experiments  show  that  cal- 
careous spar,  without  altering  its  state  of  ag- 
gregation, expands  in  the  direction  of  one  of 
its  axis  of  crystallization,  and  contracts  in  an- 
other("«). 

If  from  these  general  considerations  we  pass 
on  to  particular  examples,  we  first  observe 
schists  turned  into  black-blue  roofing  slate  by 
the  vicinity  of  Plutonic  ejected  rocks.  The 
clefts  of  stratification  are  then  interrupted  by 
another  system  of  clefts  which  cut  the  former 
almost  perpendicularly,  and  indicate  the  opera- 
tion of  a  later  influence("').  By  the  penetra- 
tion of  silicic  acid,  clay  slate,  traversed  by  frag- 


ments of  quartz,  is  partially  changed  into  whet- 
stone slate  (Wetzschiefer,  whitestone  or  Eu- 
ritel)  and  sihcious  slate  (Kieselschiefer,  quart- 
zitel),  the  latter  frequently  carboniferous,  and 
then  galvanic  in  its  effects  on  tlie  nerves.  The 
highest  degree  of  silicification  of  the  schists("«), 
however,  is  found  in  a  precious  material  em- 
ployed in  the  arts,  ribboned  jasper,  produced 
in  the  Ural  Mountains  by  the  contact  of  erup- 
tive augitic  porphyry  (Orsk),  dioritic  porphyry 
(Auschkul),  or  hypersthene  rock  (Bogoslowsk) ; 
in  the  Island  of  Elba  (Monte  Serrato),  accord- 
ing to  Fr.  Hoffmann,  and  in  Tuscany,  accord- 
ing to  Alexander  Brongniart,  by  contact  with 
euphotide  and  serpentine. 

The  contact  and  Plutonic  influence  of  granite 
cause  clay-slate  to  become  granular,  changing 
it  into  a  granitic-looking  mass — into  a  mixture 
of  felspar  and  mica,  in  which  again  larger  plates 
of  mica  lie  embedded("^> — a  fact  which  Gus- 
tavus  Rose  and  I  observed  within  the  fortress 
of  BuchtarminskC^*").  "That  the  whole  of 
the  gneiss  lying  between  the  Icy  Sea  and  the 
Gulph  of  Finland  has  been  formed  and  trans- 
formed by  the  agency  of  granite  out  of  Silurian 
strata  of  the  transition  series,  may  now,  as 
Leopold  von  Buch  has  said,  be  assumed  as  an 
hypothesis  familiar  to  all  geologists,  and  ac- 
cepted by  the  greater  number  as  demonstrated. 
In  the  Alps  of  St.  Gothard  cretaceous  marl  is 
met  with  transformed  by  granite,  ffrst  into  mi- 
caceous schist,  and  then  into  gneiss'X'^"). 
Similar  phenomena  in  respect  of  gneiss  and 
mica  slate  formations,  under  the  influence  of 
granite,  are  presented  :  in  the  Oolitic  group  of 
Tarantaise(=^*2),  where  belemnites  have  been 
found  in  rocks  that  already  lay  claim  to  the  de- 
nomination of  mica  schist ;  in  the  schistose 
group  of  the  western  portion  of  the  Island  of 
Elba,  not  far  from  Cape  Calamata,  and  in  the 
Fichtelgebirge  of  Bayreuth,  between  Lomitz 
and  Markleiten(^"). 

Precisely  as  jaspar,  a  substance  employed  in 
the  arts,  which  was  inaccessible  to  the  ancients 
in  large  masses(2**),  is  the  product  of  volcanic 
agency  upon  augitic  porphyry,  so  is  the  other 
artistic  material,  so  variously  and  so  success- 
fully employed  by  them,  granular  marble,  to  be 
regarded  as  a  sedimentary  stratum  altered  by 
the  heat  of  the  earth  and  the  vicinity  of  an 
eruptive  rock.  Careful  observation  of  phe- 
nomena of  contact,  and  the  remarkable  experi- 
ments of  Sir  James  Hall  on  the  fusion  of  rocks, 
now  more  than  half  a  century  old,  in  addition 
to  the  diligent  study  of  granitic  veins,  which 
contributed  so  essentially  to  the  early  founda- 
tions of  our  present  geology,  warrant  such  a 
conclusion.  The  protruded  rock  has  occasion- 
ally changed  the  dense  calcareous  deposit  into 
granular  limestone  to  a  certain  thickness  only, 
or  in  a  certain  zone  from  the  line  of  contact. 
We  find  a  partial  transformation,  like  a  half- 
shadow,  at  Belfast  in  Ireland,  where  basaltic 
dykes  penetrate  the  chalk ;  in  the  same  way, 
in  the  compact  floetz-limestone  near  the  bridge 
of  Boscampo,  and  by  the  waterfall  of  Canzocoli 
in  the  Tyrol,, celebrated  by  Count  Marzari  Pen- 
cati,  the  strata  have  been  partially  bent  where 
they  come  in  contact  with  a  syenitic  granite(=^**). 
Another  kind  of  transformation  is  that  in  which 
the  whole  of  the  beds  of  compact  calcareous 
rock   are    changed   into  granular   limestone 


METAMORPHOSES  OF  ROCKS. 


79 


through  the  influence  of  granite,  syenite,  or 
dioritic  porphyry^*®). 

Let  me  be  allowed  to  refer  particularly  in 
this  place  to  the  Parian  and  Carrara  marbles, 
which  have  become  so  necessary  to  the  noblest 
efforts  of  the  sculptor,  and  which  have  served 
but  too  long  in  our  geological  collections  as 
principal  types  of  primitive  limestone.  The  ef- 
fects of  the  granite  here  reveal  themselves 
partly  under  immediate  contact,  as  in  the  Pyr- 
enees("^),  partly,  as  in  the  continent  of  Greece 
and  the  islands  of  the  ^gean  Sea,  through  in- 
terposed strata  of  gneiss  and  mica  slate.  In 
both  cases  the  process  of  transformation  of  the 
calcareous  rock  is  contemporaneous,  but  dis- 
similar. It  has  been  observed  at  Cubsea,  in 
Attica,  and  in  the  Peloponnesus,  "  that  the  rule 
is,  that  the  limestone  which  rests  upon  mica 
slate  is  by  so  much  the  more  beautiful  and 
crystalline  as  the  schist  is  purer,  that  is,  as  it 
is  freer  from  argillaceous  admixture."  Mica 
slate,  as  well  as  gneiss  strata,  present  them- 
selves at  many  deep  points  of  Pares  and  Anti- 
paros(^*^).  If  marine  productions  were  discov- 
ered [in  ancient  times]  in  the  quarries  of  Syra- 
cuse, and  the  "  impression  of  a  small  fish"  was 
seen  in  the  deepest  of  the  rocks  of  Paros,  as 
we  may  infer  from  a  notice  in  Origen,  of  the 
old  Eleatic  philosopher,  Xenophanes  of  Colo- 
phon (2*^),  who  conceived  the  whole  of  the 
world  to  have  been  formerly  covered  by  the 
sea,  we  might  believe  in  the  remains  of  a  floetz 
stratum  in  this  situation  which  had  not  under- 
gone complete  metamorphosis.  The  marble 
of  Carrara  (Luna),  which  was  employed  before 
the  Augustan  age,  and  was  the  principal  source 
of  the  material  for  statues  so  long  as  the  quar- 
ries of  Paros  remained  closed,  is  a  stratum  of 
the  same  cretaceous  sandstone  (macigno)  al- 
tered by  Plutonic  agency,  which  presents  itself 
in  the  insulated  Alpine  height,  Apuana,  lying 
between  gneiss -like  micaceous  and  talcose 
schistsC^").  Whether  or  not  granular  lime- 
stone, formed  in  the  interior  of  the  earth,  and 
filling  fissures  in  the  manner  of  veins  (Auer- 
bach  on  the  Bergstrasse),  have  ever  been  forced 
to  the  surface  by  gneiss  and  syenite(='^^),  I  can- 
not, through  want  of  personal  observation,  take 
it  upon  me  to  decide. 

The  most  remarkable  metamorphoses  of 
compact  calcareous  strata,  however,  according 
to  Leopold  von  Buch's  able  observations,  are 
to  be  seen  in  the  Southern  Tyrol,  and  among 
the  Italian  slopes  of  the  Alps,  effected  princi- 
pally by  the  intrusion  of  dolomitic  masses. 
The  metamorphosis  of  the  calcareous  rock 
here  proceeds  from  fissures,  which  traverse  it 
in  all  directions.  The  clefts  are  everywhere 
covered  with  rhomboids  of  magnesian  spar ;  the 
whole  formation  indeed,  without  stratification, 
and  without  a  vestige  of  the  fossils  which  it 
formerly  included,  then  consists  exclusively  of 
a  granular  aggregation  of  dolomitic  rhomboids. 
Talc  leaves  and  transverse  fragments  of  ser- 
pentine lie  here  and  there  dispersed  through 
the  new-fashioned  rock.  In  Fassathal,  the  dolo- 
mite rises  perpendicularly  in  the  form  of  smooth 
walls  of  dazzhng  whiteness  to  the  height  of 
several  thousand  feet.  It  forms  pointed  coni- 
cal hills,  which  stand  side  by  side  in  great  num- 
bers without  touching  one  another.  Their 
physiognomical  character  brings  to  mind  that 


i  sweetly  fantastical  mountain  landscape  with 
I  which  Leonardo  da  Vinci  has  ornamented  the 
!  back-ground  of  his  portrait  of  Mona  Lisa. 
I  The  geological  features  which  we  are  here 
portraying  excite  the  imagination  as  well  as 
reflection  ;  they  are  the  work  of  an  augitic  por- 
phyry, which  has  intruded  and  produced  its  ef- 
fect, by  upheaving,  shattering,  and  transform- 
^^Si  )•  The  dolomitizing  process  is  by  no 
means  regarded  by  the  gifted  inquirer  who  first 
pointed  it  out  as  an  imparting  of  magnesian 
earth  by  the  black  porphyry,  but  as  a  change 
effected  contemporaneously  with  the  protrusion 
of  the  injected  rock  into  extensive  fissures  fill- 
ed with  vapour.  It  remains  for  future  inquiries 
to  determine  in  what  way  the  transformation 
is  effected  when  the  dolomite  occurs  in  beds 
between  limestone  strata,  without  contact  with 
the  endogenous  rock,  where  the  conduits  of 
Plutonic  influences  lie  concealed.  But  it  is  not 
perhaps  necessary,  even  here,  to  take  refuge  in 
the  old  Roman  saying,  according  to  which 
*'  much  that  is  like  in  nature  has  been  produced 
in  totally  different  ways."  If  in  an  extensive 
district  of  country,  two  phenomena,  viz.,  the 
protrusion  of  melaphyrC;  and  the  alteration  in 
crystalline  texture  and  chemical  constitution 
of  a  compact  calcareous  rock,  always  go  to- 
gether, then  may  we,  with  some  reason,  con- 
jecture, that  in  cases  where  the  second  phe- 
nomenon presents  itself  without  the  first,  the 
seeming  contradiction  in  the  non-fulfilment  is 
connected  with  certain  conditions  accompany- 
ing the  occult  principal  cause.  Should  we 
question  the  volcanic  nature  of  basalt  and  its 
state  of  liquefaction  through  fire,  because  a 
few  rare  instances  have  been  met  with  in 
which  dykes  of  this  substance  traverse  carbo- 
niferous sandstone  and  cretaceous  strata,  with- 
out the  coal  being  deprived  of  its  bitumen,  the 
sandstone  reduced  to  the  state  of  frit,  or  the 
chalk  being  turned  into  granular  marble  *? 
Where  we  meet  with  even  a  twilight  glimmer, 
with  the  faintest  trace  of  a  way  in  the  obscure 
region  of  mineral  formations,  we  must  not 
thanklessly  reject  both,  because  there  is  still 
much  unexplained  in  the  relations  of  transition 
from  one  rock  to  another,  and  in  the  isolated 
interposition  of  altered  between  unaltered 
strata. 

Besides  the  transformation  of  compact  cal- 
careous carbonate  into  granular  limestone  and 
into  dolomite,  there  is  a  third  metamorphosis 
of  the  same  deposit,  which  must  here  be  ad- 
verted to,  and  which  is  attributable  to  the  vol- 
canic eruption  of  sulphuric-acid-vapours,  in 
primeval  epochs.  This  transformation  of  lime- 
stone into  gypsum  is  connected  with  the  pene- 
tration of  rock-salt  and  sulphur  (the  latter  pre- 
cipitated from  watery  vapour  charged  with  the 
mineral).  In  the  lofty  chain  of  the  Andes  of 
Quindiu,  far  from  all  volcanoes,  I  have  myself 
observed  this  precipitate  within  fissures  in 
gneiss,  whilst  the  sulphur,  gypsum,  and  rock- 
salt  of  Sicily  (Cattolica,  near  Girgenti)  belong 
to  the  newest  secondary  strata,  or  to  the  chalk 
formations("3).  i  have  farther  seen  fissures 
filled  with  rock-salt,  in  quantities  that  some- 
times tempt  the  people  to  engage  in  an  illicit 
traflic  in  the  article,  in  the  edge  of  the  crater  of 
Vesuvius.  On  both  slopes  of  the  Pyrenees  it 
is  impossible  to  doubt  the  connection  of  diorit- 


80 


ARTIFICIAL  PRODUCTION  OF  SIMPLE  MINERALS. 


ic  (and  pyroxenic  1)  rock,  with  the  appearance 
of  dolomite,  of  gypsum,  and  of  rock-salt("*). 
Everything  in  the  phenomena  here  referred  to 
proclaims  the  influence  of  subterraneous  forces 
upon  the  sedimentary  strata  of  the  ancient 
ocean. 

The  beds  of  pure  quartz  of  enormous  magni- 
tude, which  are  so  characteristic  of  the  Andes 
of  South  America(2") — ^^d  I  may  here  state 
that  I  have  seen  such  beds  between  7  and  8,000 
feet  in  thickness,  in  the  route  from  Caxamarca 
to  Guangamarca,  descending  towards  the  south- 
ern ocean  —  are  of  enigmatical  origin.  They 
rest  in  one  place  upon  quartzless  porphyry,  in 
another  upon  dioritic  rocks.  Have  they  been 
produced  from  sandstone,  as  M.  Elie  de  Beau- 
mont conjectures  has  been  the  case  in  regard 
to  the  quartz  strata  of  the  Col  de  la  Poisson- 
niere,  to  the  east  of  Briancjon  1("®)  In  the  di- 
amond districts  of  Minas  Geraes  and  St.  Paul, 
in  Brazil,  which  have  been  lately  so  carefully 
examined  by  Clausen,  Plutonic  forces  acting 
upon  dioritic  veins  have  developed  in  one  place 
common  mica,  in  another  ferruginous  mica,  in 
the  quartzose  itacolumite.  The  diamonds  of 
Grammagoa  are  contained  in  layers  of  solid  si- 
licic acid ;  occasionally  they  lie  enveloped  by 
plates  of  mica,  exactly  like  the  garnets  formed 
in  mica-slate.  The  most  northern  of  all  the 
diamonds  which  have  been  found  since  the  year 
1829,  under  the  58th  parallel  of  north  latitude, 
on  the  European  declivity  of  the  Ural  mount- 
ains, also  stand  in  geological  relation  to  the 
black  carboniferous  dolomite  of  Adolfskoi(2^^), 
as  well  as  to  augitic  porphyry,  which  have  not 
yet  been  made  the  subject  of  sufficiently  accu- 
rate observations. 

Among  the  most  remarkable  contact-phe- 
nomena, finally,  are  comprised  the  formation 
of  garnets  in  clay-slate,  under  the  influence  of 
basalt  and  dolerite,  instances  of  which  occur  in 
the  county  of  Northumberland  and  in  the  island 
of  Anglesea  ;  and  for  the  production  of  a  great 
number  of  beautiful  and  very  dissimilar  crys- 
tals—garnets, Vesuviane,  augite,  and  Ceylanite 
— which  make  their  appearance  upon  the  con- 
tingent surfaces  of  eruptive  and  sedimentary 
rocks,  on  the  boundary  of  the  syenite  of  Mon- 
zon  with  dolomite  and  compact  limestone("^). 
In  the  island  of  Elba,  the  masses  of  serpen- 
tine, which  nowhere,  perhaps,  present  them- 
selves so  conspicuously  as  eruptive  rocks,  have 
caused  the  sublimation  of  iron  glance  and  red 
iron  stone  into  the  fissures  of  a  cretaceous 
sandstone("9).  The  same  iron  glance  is  still 
seen  every  day,  sublimed  from  vapour,  upon 
the  edges  of  open  fissures  in  the  craters  of 
Stromboli,  Vesuvius,  and  ^Etna,  and  in  cracks 
of  the  recent  lava  streams  of  these  volca- 
noesC^fiO).  As  we  here  perceive  the  materials 
of  veins  produced  under  the  influence  of  volcan- 
ic forces  before  our  eyes,  and  where  the  neigh- 
bouring rock  has  already  attained  to  a  state  of 
solidity,  we  conceive  how  mineral  and  metallic 
veins  may  have  been  produced  during  the  ear- 
lier revolutions  of  the  crust  of  the  earth  ;  when 
the  solid,  but  still  thin  shell  of  the  planet,  re- 
peatedly shaken  by  earthquakes,  shattered  and 
rifted  by  alterations  in  its  volume  occasioned  by 
cooling,  presented  numerous  communications 
with  the  interior,  numerous  outlets  for  vapours 
laden  with  earthy  and  metallic  substances. 


1  The  stratified  arrangement  of  the  mineral 
I  matters  parallel  with  the  surfaces  bounding 
veins,  the  regular  repetition  of  similar  layers 
on  both  sides,  on  the  roofs  and  on  the  floors  of 
veins,  and  the  druses  or  elongated  cavities  of 
their  middles,  indeed,  frequently  bear  imme- 
diate testimony  to  a  Plutonic  process  of  subli- 
mation in  metalliferous  veins.  As  the  matter 
traversing  is  of  more  recent  origin  than  the 
matter  traversed,  we  learn  from  the  relations 
of  position  of  the  porphyry  to  the  silver-ore 
formations  of  the  Saxon  Erzgebirge,  that  these, 
in  the  mountains  which  are  richer  in  mineral 
treasures  than  any  others  in  Germany,  are  at 
least  younger  than  the  trunks  of  trees  of  the 
coal  formation  and  than  the  lower  new  red 
sandstone  (Rothliegendes)  ("*). 

All  our  geological  speculations,  in  regard  to 
the  formation  of  the  crust  of  the  earth  and  the 
metamorphosis  of  rocks,  have  had  unexpected 
light  thrown  on  them,  by  the  happy  idea  of  as- 
similating the  production  of  scoriae  in  our  smelt- 
ing furnaces,  to  the  formation  of  natural  min- 
erals, and  of  reproducing  these  artificially  from 
their  elements(2").  The  same  affinities,  de- 
termining chemical  combinations,  come  into 
play  in  all  these  operations,  whether  they  be 
conducted  in  our  laboratories  or  in  the  bosom 
of  the  earth.  The  most  important  simple  min- 
erals, characterizing  the  very  generally  distrib- 
uted Plutonic  and  volcanic  rocks,  as  well  as 
those  that  have  suffered  metamorphosis  through 
them,  have  been  found  in  our  artificial  mineral 
formations  in  the  crystalline  state,  and  like  the 
natural  ones  in  all  respects.  We  distinguish 
those  that  have  arisen  accidentally  in  scoriae, 
from  those  that  have  been  produced  intention- 
ally by  chemists.  To  the  former  belong  fel- 
spar, mica,  augite,  olivine,  blende,  crystalline 
oxide  of  iron  (iron  glance),  octohedral  magnet- 
ic iron,  and  metallic  titanium(='^^) ;  to  the  lat- 
ter garnet,  idokras,  ruby  (equal  in  hardness  to 
the  Oriental  stone),  olivine,  and  augite(=«*). 
The  minerals  now  named  form  the  principal 
constituents  of  granite,  gneiss,  and  mica  schist, 
of  basalt,  dolerite,  and  numerous  porphyries. 
The  artificial  production  of  felspar  and  mica,  in 
particular,  is  of  signal  geological  importance 
for  the  theory  of  the  formation  of  gneiss  by  the 
transformation  of  clay  slate.  This  contains  the 
elements  of  granite,  potash  not  excepted('"). 
It  would  not,  therefore,  be  any  thing  very  ex- 
traordinary, as  an  acute  geologist,  M.  von 
Dechen,  has  observed,  were  we  one  day  to  find 
a  piece  of  gneiss  produced  upon  the  walls  of  a 
smelting-furnace  built  of  clay-slate  and  grey- 
wacke. 

In  these  general  considerations  on  the  solid 
crust  of  the  earth,  and  after  having  indicated 
three  original  forms  of  production  in  reference 
to  its  mineral  masses,  viz.,  Eruptive,  Sediment- 
ary, and  Metamorphosed  rocks,  there  still  re- 
mains a  fourth  class,  the  Conglomerated,  or 
fragmentary,  to  wit.  This  title  of  itself  brings 
to  mind  the  denudations  or  destructions  which 
the  surface  of  the  earth  has  suffisred ;  but  it 
also  farther  reminds  us  of  the  process  of  ce- 
mentation or  agglutination  that  has  been  ef- 
fected by  oxide  of  iron,  and  by  argillaceous  and 
calcareous  [and  silicious]  cements,  by  which  in 
one  case  rounded,  in  another  angular,  frag- 
ments have  been  again  united.    Conglomerates 


PALiGOZOOLOGY. 


81 


Rnd  breccias,  in  the  widest  sense  of  these  words, 
reveal  the  character  of  a  two-fold  mode  of  ori- 
gin. The  materials  of  which  they  are  mechan- 
ically composed  have  not  always  been  accumu- 
lated by  the  waves  of  the  sea,  or  by  streams 
of  fresh  water  in  motion  ;  there  are  fragment- 
ary rocks  in  the  production  of  which  the  shock 
or  the  action  of  water  has  had  no  part.  "  When 
basaltic  islands,  or  trachytic  mountains,  arise 
upon  fissures,  the  friction  of  the  rock  as  it  as- 
cends against  the  sides  of  the  fissure  causes  ba- 
salt and  trachyte  to  become  surrounded  by  ag- 
glomerates of  their  own  masses.  The  grains 
of  which  the  sandstones  of  many  formations 
consist  have  been  more  detached  by  the  attri- 
tion of  outbreaking  volcanic,  or  Plutonic  rocks, 
than  produced  by  the  motion  of  a  neighbouring 
ocean.  The  existence  of  such  attrition-con- 
glomerates, which  are  encountered  in  enormous 
masses  in  both  divisions  of  the  globe,  bear  wit- 
ness to  the  intensity  of  the  force  with  which 
the  eruptive  masses  have  been  forced  to  the 
surface  from  the  interior.  The  waters  then 
obtained  power  over  the  smaller  detached  gran- 
ules, and  spread  them  out  in  layers  which  they 
themselves  covered'X'^*^).  Sandstone  forma- 
tions are  found  intercalated  among  all  the 
strata,  from  the  lower  Silurian  transition  se- 
ries, to  this  side  the  chalk  in  the  tertiary  for- 
mation. On  the  edges  of  the  vast  plains  of  the 
New  World,  both  within  and  without  the  trop- 
ics, they  are  seen  as  walls  or  bulwarks,  indica- 
ting, as  it  seems,  the  coasts  against  which  the 
mighty  waves  of  a  former  ocean  once  dashed 
themselves  into  foam. 

If  we  venture  a  glance  at  the  geographical 
distribution  of  rocks,  and  their  relations  in 
point  of  place  in  that  portion  of  the  crust  of  the 
earth  which  is  accessible  to  our  observation, 
we  perceive  that  the  most  generally  distributed 
chemical  material  of  all  is  silicic  acid,  either  in 
the  transparent  and  colourless  state,  or  opaque 
and  variously  tinged.  After  solid  silicic  acid 
comes  carbonate  of  lime  ;  then  follow  in  order 
the  compounds  of  silicic  acid  with  alumina, 
with  potash  and  soda,  with  lime,  magnesia,  and 
oxide  of  iron.  If  the  masses  which  we  call 
rocks  be  definite  associations  of  a  small  number 
of  minerals,  to  which  a  few  others,  but  also  of 
determinate  kinds  only,  are  added  as  parasites ; 
if,  in  the  eruptive  rock  granite,  the  association 
of  quartz  (silicic  acid),  felspar  and  mica  be  the 
essentials,  so  do  these  minerals,  either  isolated 
or  in  pairs,  present  themselves  in  many  other 
strata.  With  a  view  of  illustrating  by  an  ex- 
ample how  quantitative  relations  distinguish  a 
felspathic  rock  from  another  abounding  in  mica, 
I  here  remind  the  reader,  as  Mitscherlich  has 
done,  that  if  three  times  more  alumina,  and 
one  third  more  silicic  acid  than  belong  to  it 
naturally  be  added  to  felspar,  we  have  the  com- 
position of  mica.  Potash  is  contained  in  both, 
a  substance  the  existence  of  which  in  many 
mineral  masses  reaches  far  beyond  the  com- 
mencement of  everything  like  vegetation  on 
the  surface  of  the  earth. 

The  succession,  and  with  this  the  age  of  the 
several  formations,  are  ascertained  or  deter- 
mined by  the  reciprocal  position  of  the  Sedi- 
mentary, Metamorphic,  and  Conglomerate  stra- 
ta, by  the  nature  of  the  formations  up  to  which 


the  Eruptive  masses  ascend,  but  most  certain- 
ly and  safely  by  the  presence  of  organic  re- 
mains and  the  diversities  of  their  structure. 
The  application  of  Botanical  and  Zoological 
knowledge  to  the  determination  of  the  age  of 
rocks,  the  chronomcfry  of  the  crust  of  the  earth, 
which  Hook's  great  spirit  had  already  di- 
vined(»«^),  marks  one  of  the  most  brilliant  ep- 
ochs in  the  progress  of  geology,  now  finally  ab- 
stracted, on  the  Continent  at  least,  from  Se- 
mitic influences.  Palaeontological  studies  have, 
as  with  a  vivifying  breath,  given  grace  and  the 
charms  of  variety  to  the  doctrine  of  the  solid 
materials  of  the  globe. 

The  fossiliferous  strata  present  us  with  the 
entombed  floras  and  faunas  of  bygone  millen- 
niums. We  ascend  in  time,  whilst,  penetra- 
ting downwards  from  layer  to  layer,  we  deter- 
mine the  relations  in  space  of  the  several  for- 
mations. An  animal  and  vegetable  existence 
that  has  passed  away  is  brought  to  light. 
Wide-spread  revolutions  of  the  globe,  the  up- 
heaval of  mighty  mountain  chains,  whose  rela- 
tive ages  we  are  in  a  condition  to  determine, 
denote  the  destruction  of  old  organic  forms, 
the  appearance  of  new.  A  few  of  the  older 
still  show  themselves  for  a  time  among  the 
newer  forms.  In  the  narrowness  of  our  knowl- 
edge of  original  production,  in  the  figurative 
language  with  which  this  circumscription  of 
view  is  concealed,  we  designate  as  new  crea- 
tions the  historical  phenomena  of  change  in  the 
organisms,  as  in  the  tenancy  of  the  primeval 
waters,  and  of  the  uphfted  dry  land.  These 
extinct  organic  forms  are  in  one  case  pre- 
served entire,  even  to  the  most  minute  details 
of  covering  and  articulated  parts  ;  in  other  in- 
stances nothing  more  remains  of  them  than 
their  footsteps  imprinted  on  the  wet  sand  or 
mud  which  they  traversed  when  alive,  or  their 
coprolites  (petrified  dejections),  containing  the 
unassimilated  portions  of  the  food  upon  which 
they  fed.  In  the  lower  Jura  formation  (the 
Lias  of  Lyme  Regis),  the  preservation  of  the 
ink-bag  of  the  sepia("0>  is  so  wonderfully  per- 
fect, that  the  same  material  which  the  animal 
employed  myriads  of  years  before  to  preserve 
itself  from  its  enemies,  has  been  made  to  serve 
as  the  colour  wherewith  to  paint  its  likeness. 
In  other  strata  there  is  sometimes  nothing 
more  than  the  faint  impression  of  a  bivalve 
shell,  and  yet  will  this  suffice,  when  brought 
by  a  traveller  from  a  far  distant  country,  if  it 
be  a  characteristic  shell  (Leitmuschel,  a  gui- 
ding-shell) ("8)  to  inform  us  of  the  material  for- 
mations which  there  exist,  and  of  the  other  or- 
ganic remains  with  which  it  was  associated  ;  it 
tells  the  history  of  the  district  whence  it  came. 

The  anatomical  study  of  the  ancient  animal 
and  vegetable  life  of  the  globe  extends  in  a 
two-fold  direction.  The  one  is  purely  morpho- 
logical in  its  bearings,  and  is  especially  devo- 
ted to  the  description  and  physiology  of  the  or- 
ganisms ;  it  fills  up  with  extinct  forms  the  gaps 
encountered  in  the  series  that  still  exist.  The 
other  direction  is  geological,  and  considers  fos- 
sil organic  remains  in  their  relations  to  the  su- 
perposition and  relative  age  of  the  sedimentary 
formations.  The  first  was  long  the  usual  di- 
rection taken,  and  in  its  imperfect  and  superfi- 
cial comparisons  of  petrifactions  with  living  spe- 
cies led  off  into  erroneous  ways,  traces  of  which 


82 


PALiEOZOOLOGY. 


are  still  to  be  discovered  in  the  extraordinary 
denominations  of  certain  natural  bodies.  There 
was  the  constant  disposition  to  recognize  a  liv- 
ing in  every  extinct  species  ;  just  as,  in  the 
16th  century,  false  analogies  led  naturalists  to 
confound  the  animals  of  the  Old  World  vv^ith 
those  of  the  New  Continent.  Camper,  Soem- 
mering, and  Blumenbach,  had  the  merit,  by  the 
scientific  application  of  a  better  comparative 
anatomy,  of  first  illustrating  the  osteological 
portion  of  Palaeontology  (the  Archaeology  of  or- 
ganic life),  in  so  far  at  least  as  the  larger  fos- 
sil vertebrate  animals  are  concerned ;  but  for 
the  proper  geological  consideration  of  the  Sci- 
ence of  Petrifactions,  for  the  happy  combina- 
tion of  the  zoological  character  with  the  age 
and  order  of  deposition  of  strata,  we  are  in- 
debted to  the  great  work  of  George  Cuvier  and 
Alexander  Brongniart. 

The  oldest  sedimentary  formations,  those  to 
wit  of  the  transition  series,  in  the  organic  re- 
mains which  they  include,  present  a  mixture  of 
forms  which  assume  very  diflerent  places  in 
the  scale  of  development,  gradually  attaining  to 
greater  and  greater  perfection.  Of  vegetables, 
they  contain  indeed  but  a  few  Fuci,  Lycopo- 
diaceae  which  perhaps  were  arborescent,  Equi- 
setaceae,  and  tropical  Ferns  ;  but  of  animal  re- 
mains, we  find,  strangely  associated  together, 
Crustacea  (trilobites  with  reticular  eyes,  and 
calymene),  Brachiopoda  (spirifer,  orthis),  the 
elegant  Spheronites,  which  are  nearly  allied 
to  the  crinoideae("5)  and  orthoceratites  from 
among  the  Cephalopoda,  Stone-cora!s,  and  with 
these  lower  organisms,  Fishes  of  singular  forms 
in  the  upper  Silurian  strata.  The  heavily-arm- 
ed family  of  Cephalaspidans,  fragments  from 
whose  genus  Pterychthys  were  long  regarded 
as  trilobytes,  belong  exclusively  to  the  Devo- 
nian, or  old  red  sandstone  formation,  and  show, 
as  Agassiz  says,  as  peculiar  a  type  in  the  se- 
ries of  fishes  as  Ichthyosauri  and  Plesiosauri 
do  among  the  reptiles(2'°).  The  Goniatites, 
belonging  to  the  group  of  Ammonites,  likewise 
begin  to  show  themselves  in  the  transition 
limestone  and  greywacke  of  the  Devonian,  and 
even  in  the  later  members  of  the  Silurian  sys- 
tem(2"). 

The  dependence  of  physiological  gradation 
upon  the  age  of  the  formation,  which  has  hith- 
erto been  but  little  observed  in  the  position  of 
the  invertebrate  order  of  animals(2"),  is  exhib- 
ited in  the  most  regular  manner  in  connection 
with  the  vertebrate  series.  The  oldest  of  these, 
as  we  have  just  seen,  are  the  fishes  ;  and  then, 
following  the  series  of  formations  from  the  in- 
ferior to  the  superior,  we  come  to  reptiles  and 
mammalia.  The  first  reptile  encountered,  a 
saurian  or  lizard,  and,  according  to  Cuvier,  a 
monitor,  which  had  already  attracted  the  at- 
tention of  Leibnitz(=^^3),  makes  its  appearance 
in  the  copperslate  floetz  of  the  Zechstein  [low- 
er new  red,  or  magnesian  limestone  formation], 
of  Thuringia  ;  and  with  this,  and  of  the  same 
age,  according  to  Murchison,  the  palaeosaurus 
and  the  codontosaurus  of  Bristol.  The  Sau- 
rians  go  on  increasing  in  numbers  in  the  Mus- 
chelkalk,  in  the  Keuper,  and  in  the  Jura  forma- 
tion, in  which  they  attain  their  maximumC^*^*). 
Contemporaneously  with  this  formation  lived 
Plesiosauri,  with  long  swan-like  necks,  con- 
taining thirty  vertebrae  ;  the  Megalosaurus,  a 


crocodilian  monster,  45  feet  long,  and  with 
bones  of  the  feet  like  those  of  a  heavy  mam- 
miferous  land  animal ;  eight  species  of  large- 
eyed  Ichthyosauri ;  the  Geosaurus  or  Soem- 
mering's  Lacerta  gigantea ;  finally,  seven  sin- 
gularly hideous  Pterodactyles(=^"),  or  Saurians 
furnished  with  membranous  wings.  In  the 
chalk,  the  number  of  crocodilian  Saurians  falls 
off,  yet  the  epoch  which  this  deposit  charac- 
terizes is  distinguished  by  the  Maestricht  croc- 
odile, as  it  is  called,  the  Mososaurus  of  Cony- 
beare,  and  the  colossal,  perhaps  herbivorous, 
Iguanodon.  Other  animals  that  belong  to  the 
present  race  of  crocodiles  Cuvier  has  met  with 
ascending  into  the  tertiary  formations(^'*) ;  and 
Scheuchzer's  "  Man  attesting  the  deluge  (ho- 
mo diluvii  testis),"  a  great  salamander,  allied 
to  the  axolotl,  which  I  brought  with  me  from 
the  Mexican  lakes,  belongs  to  the  newest  fresh- 
water formations  of  Oeningen. 

The  relative  ages  of  organisms  determined 
by  the  position  of  the  rocky  strata  in  which 
their  remains  are  found,  has  led  to  important 
conclusions  as  to  the  relations  that  can  be 
traced  between  extinct  and  still  existing  fami- 
lies and  species  (the  latter,  the  species,  in  very 
small  numbers).  Older  and  newer  observa- 
tions agree  in  showing  that  the  floras  and  fau- 
nas are  by  so  much  the  more  unlike  the  pres- 
ent forms  of  plants  and  animals,  as  the  sedi- 
mentary formations  in  which  their  remains  lie 
buried  belong  to  the  inferior ;  in  other  words, 
to  the  older  strata.  The  numerical  relations 
presented  by  these  grand  successive  changes 
in  the  forms  of  organic  life,  first  pointed  out  by 
Cuvier,  have  yielded  decisive  results  through 
the  meritorious  labours  of  Deshayes  and  Lyell, 
in  connection  more  especially  with  the  various 
groups  of  the  tertiary  formations,  which  con- 
tain a  considerable  mass  of  carefully-studied 
forms.  Agassiz,  who  has  cognizance  of  1700 
species  of  fossil  fishes,  and  who  estimates  the 
number  of  living  species  that  have  been  de- 
scribed, or  that  are  preserved  in  museums,  at 
8000,  speaks  out  quite  decisively,  in  his  mas- 
ter-work. He  says  :  "  With  the  single  excep- 
tion of  one  small  fossil  fish,  peculiar  to  the  clay- 
geodes  of  Greenland,  I  have  found  no  animal  of 
this  class  in  all  the  transition,  floetz,  and  ter- 
tiary strata,  which  is  specifically  identical  with 
any  fish  now  living;"  and  he  adds  the  follow- 
ing important  observation  :  "  In  the  inferior 
tertiary  formations,  the  coarse  limestone  and 
London  clay,  for  example,  one-third  of  the  fos-  j 
sil  fishes  even  belong  to  genera  that  are  w^hoUy  i 
extinct ;  below  the  chalk  there  is  not  one  of  ] 
the  genera  of  fishes  of  the  present  time  to  be 
found,  and  the  extraordinary  family  of  the  Sau- 
roids  (or  fishes  with  scales  covered  with  en- 
amel, which  in  structure  almost  approach  rep- 
tiles, and  ascend  from  the  coal  formation,  in 
which  the  largest  species  lie  embedded,  to  the 
chalk,  where  single  individuals  are  still  en- 
countered), stand  related  to  the  two  families 
Lepidosteus  and  Polypterus,  which  now  inhab- 
it the  rivers  of  America  and  the  Nile,  in  the 
same  way  as  our  present  elephants  and  tapirs 
to  the  Mastodons  and  Anaplotheriums  of  the 
primeval  world"^"). 

The  chalk-beds,  however,  which  still  contain 
two  of  these  sauroid  fishes,  and  gigantic  rep- 
tiles, and  which  present  themselves  as  an  en- 


PALiGOZOOLOGY. 


83 


tire  world  of  extinct  corals  and  shells,  are  com- 
posed, according  to  Ehrenberg's  beautiful  dis- 
covery, of  microscopic  Polythalamia,  many  of 
which  are  still  to  be  found  in  our  seas,  particu- 
larly in  the  middle  latitudes  of  the  North  Sea 
and  Baltic.  The  first  group  of  the  tertiary 
formation  lying  over  the  chalk,  a  group  which 
it  has  become  customary  to  designate  by  the 
name  of  the  strata  of  the  Eocene  period,  would 
appear  by  no  means  rightly  to  deserve  this 
title  —  "inasmuch  as  the  morning  dawn  of 
the  nature  that  still  exists  with  us  extends  far 
more  deeply  into  the  history  of  the  earth  than 
was  until  lately  believed"(^™). 

As  fishes,  the  oldest  of  all  vertebrate  animals, 
already  show  themselves  in  Silurian  transition 
strata,  and  then  occur  without  interruption  in 
all  subsequent  formations  up  to  the  strata  of 
the  tertiary  epoch ;  as  we  have  seen  the  Sau- 
rians  begin  with  the  zechstein  or  magnesian 
limestone,  so  are  the  first  raammiferous  ani- 
mals, the  Thylactotherium,  Prevostii,  and  T. 
Bucklandii,  which  Valenciennes  regards  as  near- 
ly allied  to  the  Marsupialia(=^'),  found  in  the 
Stonesfield  slate,  a  lower  member  of  the  Jura 
or  Oolitic  formation,  and-  the  first  bird  occurs 
in  the  older  cretaceous  depositsC*").  These, 
according  to  our  present  knowledge,  are  the 
inferior  limits  of  fishes,  saurians,  mammalia, 
and  birds. 

But  if,  among  the  members  of  the  inverte- 
brate series  of  animals,  stone  corals  and  serpu- 
lites  are  found  making  their  appearance  in  the 
oldest  formations  simultaneously  with  highly 
developed  cephalopods  and  Crustacea,  the  most 
different  and  dissimilar  orders  being,  therefore, 
associated  without  distinction,  we,  on  the  oth- 
er hand,  discover  very  determinate  laws  in 
connection  with  the  distribution  of  particular 
groups  of  the  same  orders.  Fossil  shells  of  the 
same  kinds,  goniatites,  trilobites,  and  nummu- 
lites,  compose  entire  mountains.  Where  dif- 
ferent genera  are  mingled,  it  often  happens 
that  not  only  is  there  a  determinate  sequence 
of  organisms  recognizable,  according  to  the  re- 
lations of  superposition  in  the  several  systems 
of  strata,  but  the  association  of  certain  genera 
and  species  has  also  been  observed  in  the  sub- 
ordinate strata  of  the  same  formations.  By 
his  happy  discovery  of  the  Law  of  Estimates 
(Lobenstellung),  Leopold  von  Buch  has  been 
enabled  to  distribute  the  vast  multitude  of  am- 
monites into  well-characterized  families,  and 
shown  how  the  ceratites  belong  to  the  mus- 
chelkalk,  the  arietes  to  the  lias,  the  goniatites 
to  the  transition  limestone  and  greywacke("^). 
Belemnites  have  their  inferior  limits  in  the 
Keuper  -vvhich  covers  the  Jura  limestone,  their 
superior  limits  in  the  chalk("2).  The  waters 
of  countries  far  remote  from  one  another  were 
inhabited  at  the  same  epochs  by  testaceous  an- 
imals, which  partly  at  least,  as'  is  now  known 
for  certain,  are  identical  with  those  that  occur 
fossilized  in  Europe.  Leopold  von  Buch  has 
shown  us  exogyri  and  trigonia  from  the  south-  | 
ern  hemisphere  (the  volcano  Maypo,  in  Chili),  I 
and  d'Orbigny  ammonites  and  gryphese  from  i 
the  Himalaya  mountains  and  the  plains  of  Cutch 
in  India,  which  are  identical  in  kind  with  those 
left  behind  by  the  old  Jurassic  sea  of  France 
and  Germany. 

Strata  characterized  by  determinate  species 


of  fossils,  or  by  determinate  rolled  masses 
which  they  inclose,  form  a  geognostical  hori- 
zon, by  means  of  which  the  geologist,  when  at 
a  loss,  can  always  ascertain  his  place,  and  pur- 
suing which,  he  arrives  at  safe  conclusions  as 
to  the  identity  and  relative  age  of  certain  for- 
mations, the  periodical  recurrence  of  particular 
strata,  their  parallelism,  and  their  total  sup- 
pression or  failure.  If  we  will  thus  embrace 
the  type  of  the  sedimentary  formation  in  its 
greatest  simplicity  and  most  general  distribu- 
tion, we  find  its  members  in  the  following  or- 
der, proceeding  from  below  upwards. 

1st.  The  so-called  Transition  rocks,  in  the 
two  divisions  of  inferior  and  superior  grey- 
wacke,  or  Silurian  and  Devonian  systems,  the 
latter  formerly  designated  the  Old  Red  Sand- 
stone formation  ; 

2d.  The  inferior  Trias('*') — Mountain  lime- 
stone, the  Coal  measures  together  with  the 
Red  conglomerate  (Todtlregendes),  and  Zech- 
stein or  Magnesian  limestone  ; 

3d.  The  superior  Trias  —  Variegated-sand- 
stone, Musehelkalk  and  Keuper(28*); 

4th.  Jura  limestone  (Lias  and  Oolite) ; 

5th.  Massive  sandstone,  Inferior  and  Superi- 
or chalk,  as  the  last  of  the  floetz  strata,  which 
begin  with  the  mountain  limestone  ; 

6th.  Tertiary  formations,  in  three  divisions, 
which  are  indicated  by  the  Coarse  limestone, 
Brown  coal  or  Lignite,  and  Sub-Apennine 
gravel. 

In  the  alluvium  or  drift  follow  the  gigantic 
bones  of  the  extinct  mammalia — the  Masto- 
dons, Dinotheriums,  Missuriums,  Megatheri- 
ums, Owen's  Sloth-like  Mylodon,  1 1  feet  long, 
&c.  With  these  primaeval  genera  are  associa- 
ted the  fossilized  remains  of  many  animals  that 
still  exist — the  elephant,  rhinoceros,  ox,  horse, 
deer,  &c.  The  plain  near  Bogota,  filled  with 
the  bones  of  Mastodons  (the  Campo  de  Gigan- 
tes,  in  which  I  had  some  careful  digging  per- 
formed) (2"),  lies  8,200  feet  above  the  level  of 
the  sea,  and  the  bones  of  extinct  species  of  true 
elephants  are  found  still  higher  in  the  lofty  pla- 
teaus of  Mexico.  Like  the  chain  of  the  Andes, 
which  has  certainly  been  upheaved  at  very  dif- 
ferent epochs,  the  advances  of  the  Himalaya, 
the  Sewalik  hills  (which  Captain  Cautley  and 
Dr.  Falconer  have  so  carefully  examined),  be- 
sides the  extinct  Mastodon,  Sivatherium,  and 
gigantic  land  tortoise,  the  Colossochelys,  12 
feet  long  and  6  feet  high,  contain  remains  of 
genera  that  still  exist — elephants,  rhinoceroses, 
giraffes ;  and  this,  which  is  very  much  to  be 
regarded,  within  a  zone  which  enjoys  the  same 
tropical  climate  at  the  present  day  which  we 
may  be  permitted  to  conjecture  prevailed  du- 
ring the  epoch  of  the  Mastodons(="). 

After  having  thus  compared  the  series  of  in- 
organic formations  composing  the  crust  of  the 
earth,  with  the  animal  remains  which  lie  buried 
in  them,  we  have  still  to  write  another  chapter 
in  the  history  of  the  organic  life  of  the  globe — 
that,  namely,  which  refers  to  vegetables  ;  and 
to  trace  the  epochs  of  vegetation,  the  floras 
varying  with  the  increasing  dimensions  of  the 
dry  land,  and  the  modifications  which  the  at- 
mosphere underwent. 

The  oldest  transition  strata,  as  already  re- 


84 


PALiEOPHYTOLOGY. 


marked,  present  us  with  nothing  but  cellular- 
leaved  marine  plants.     It  is  in  the  Devonian 
strata  that  a  few  cryptogaraic  forms  of  vascular 
vegetables,  calamites  and  lycopodiaceae,  are 
first  encountered^"^).     Nothing  seems  to  tes- 
tify, as,  on  theoretical  views  On  the  simflicitrj 
of  the  first  forms  of  organic  life,  it  has  been  as- 
sumed, that  vegetable  life  was  awakened  sooner 
than  animal  life,  upon  the  face  of  the  old  earth, 
and  that  this  was  brought  about  or  determined 
by  that.     The  existence  of  races  of  men  in  the 
very  northern  polar  zones,  who  subsist  on  the 
flesh  of  fish,  and  seals  and  whales,  is  enough 
of  itself  to  assure  us  of  the  possibility  of  living 
without  vegetable  matter  of  any  kind.     After 
the  Devonian  strata  and  the  mountain  lime- 
stone, comes  a  formation,  the  botanical  anato- 
my of  which  has  made  such  brilliant  progress 
in  recent  timesC^^^).     The  Coal  Formation  com- 
prises not  only  fern-like   cryptogamic  plants, 
and  phanerogamous  monocotyledons — grasses, 
yucca-like  liliaceous  vegetables  and  palms  ;  it 
further  contains  gynospermic  dicotyledons — 
coniferae  and  cycadeas.     Nearly  400  species 
from  the  flora  of  the  coal  formation  are  al- 
ready known.     I  here  mention  only  arborescent 
calamites  and  lycopodiaceae ;  scaly  lepidoden- 
drons  ;  sigillariae  of  60  feet  long,  and  occasion- 
ally found  standing  erect  and  rooted,  and  dis- 
tinguished by   a  double   vascular  fasciculate 
system ;  cactus-like  stigmariae  ;  a  host  of  ferns 
now  arborescent,  and  again  mere  fronds,  and  by 
their  quantity  proclaiming  the  still  entirely  insu- 
lar character  of  the  dry  land^^^^) ;  cycadeaeC"") ; 
and  particularly  palms(2")  in  small  numbers, 
asterophyllites  with  verticillate  leaves,  allied  to 
the  Najades  ;  araucaria-like  coniferae(292)  with 
slight  indications  of  annual  rings.     The  diver- 
sity in  character  of  a  vegetation  which  flour- 
ished luxuriantly  on  the  uplifted  and  dry-laid 
portions  of  the  old  red  sandstone,  from  the 
vegetable  world  of  the  present  time,  still  contin- 
ues through  the  later  phytological  periods  on 
to  the  last  layers  of  the  chalk(=^") ;  but  with  a 
great  degree  of  strangeness  in  the  forms,  the 
flora  of  the  coal  formation  still  exhibits  a  very 
remarkable  uniformity  in  the  distribution  of  the 
same  genera  (if  not  always  of  the  same'  spe- 
cies), over  every  part  of  the  then  surface  of  the 
earth;  in  New  Holland,  Canada,  Greenland, 
and  Melville  Island,  the  genera  are  still  the 
same. 

The  vegetation  of  the  former  world  presents 
us  with  forms  the  affinities  of  which  with  vari- 
ous families  of  the  present  age  remind  us  that 
with  them  many  intermediate  members  in  the 
series  of  organic  developments  have  perished. 
To  quote  two  instances  only :  the  Lepidoden- 
dra,  according  to  Lindley,  stand  between  the 
Coniferae  and  the  Lycopoditeae("*) ;  the  Arau- 
carita  and  Pinita,  on  the  other  hand,  in  the 
combination  of  their  vascular  fascicles,  exhibit 
something  that  is  foreign  and  peculiar.  But 
confining  our  views  to  the  present  order  of 
things,  the  discovery  of  Cycadeae  and  Coniferae 
in  the  flora  of  the  old  coal  measures  in  juxta- 
position with  Sagenaria  and  Lepidodendra,  is 
still  of  great  significance.  The  Coniferae,  to 
wit,  have  not  only  relationships  with  the  Cupu- 
liferae  and  the  Betulineae,  by  the  side  of  which 
we  encounter  them  in  the  brown-coal  forma- 
tion, but  they  are  further  connected  with  the 


Lycopoditeae.  The  family  of  the  sago-like  Cy- 
cadeas  approaches  the  Palms  in  external  appear- 
ance, whilst  agreeing  essentially  with  the  Co- 
niferae in  the  structure  of  the  flowers  and 
fruitC^'^).  Where  several  series  of  coal  strata 
lie  over  one  another,  the  genera  and  species 
are  not  always  mixed  ;  they  are  rather  and  for 
the  major  part  generically  arranged,  so  that 
only  Lycopodites  and  certain  Ferns  occur  in 
one  series  of  beds,  and  Stigmariae  and  Sigilla- 
riae in'gripther. 

In  order  to  form  an  idea  of  the  luxuriance  of 
vegetation   in  the  former  world,  and   of  the 
masses  of  vegetable  matter  accumulated  by 
running  water,  and  which  have  very  certainly 
been  converted  into  coal  in  the  humid  way(^^*), 
I  remind  the  reader  that  in  the  Saarbriicic  coal 
field  there  are  120  seams  of  coal  lying  one  over 
another,  exclusive  of  a  host  of  smaller  seams 
less  than  a  foot  in  thickness ;  that  there  are 
single  seams  of  coal  of  30  and  even  of  more 
than  50  feet  thick,  as  at  Johnstone  in  Scotland, 
and  Creuzot  in  Burgundy ;  whilst  in  the  forest 
regions  of  our  temperate  zone,  the  carbon  which 
the  trees  of  a  certain   superficial  extent  of 
ground  contain,  would  not  cover  this  surface 
with  a  layer  of  much  more  than  half  an  inch  ia 
thickness  (7  lines)  in  the  course  of  one  hundred 
years(^").    Near  the  mouth  of  the  Mississippi, 
and  in  the  wood  hillocks,  as  they  have  been  call- 
ed, of  the  Siberian  Icy  Sea,  described  by  Ad- 
miral Wrangel,  however,  there  is  at  the  present 
time  such  an  accumulation  of  trunks  of  trees, 
such  a  quantity  of  drift  wood,  washed  down  by 
land  streams,  and  brought  together  by  ocean 
currents,  that   the   phenomena  remind  us  at 
once  of  the  events  which  took  place  in  the  in- 
land waters  and  insulated  bays  of  the  primeval 
world,  and  gave  occasion  to  the  production  of 
the  coal  formations  which  we  now  discover 
hundreds  of  feet  below  the   surface  of  the 
ground.     It  is  also  well  to  remember  that  these 
coal  measures  are  indebted  for  no  inconsidera- 
ble portion  of  their  materials  not  to  the  trunks 
of  mighty  trees,  but  to  small  grasses,  and  to 
frondiferous  and  low  cryptogamic  vegetables. 

The  association  of  palms  and  cone-bearing 
trees  which  we  have  just  signalized  in  the  coal 
fields,  continues  through  almost  all  the  forma- 
tions onwards  to  far  into  the  tertiary  period. 
In  the  present  world  they  seem  rather  to  fly 
each  other's  vicinity.  We  have,  in  fact,  al- 
though improperly,  habituated  ourselves  so 
much  to  regard  the  cone-bearers  as  northern 
forms,  that  I  myself,  ascending  from  the  shores 
of  the  South  Sea  towards  Chilpansingo  and  the 
elevated  valleys  of  Mexico,  was  somewhat 
amazed  when  I  found  myself  between  Venta 
de  la  Moxonera  and  the  Alto  de  los  Caxones, 
3,800  feet  above  the  level  of  the  sea,  riding  for 
a  whole  day  through  a  dense  forest  of  the  Pinus 
occidentalis,  in  which  this  cone-bearing  tree, 
so  like  our  Lord  Weymouth's  or  white  pine, 
was  associated  with  a  fan-leaved  palm — the 
Corypha  dulcis,  covered  with  flights  of  gay 
coloured  parrots(*'^).  Southern  America  pro- 
duces oaks,  but  not  a  single  species  of  pine ; 
and  the  first  time  that  I  again  encountered  the 
familiar  form  of  a  fir-tree,  it  met  me  in  the  es- 
tranging presence  of  a  palm  with  its  fan-like 
leaves.  In  the  north-east  end  of  the  Island  of 
Cuba,  too,  and  so  within  the  tropics,  but  scarcely 


PALiEOPETROLOGY. 


86 


raised  above  the  level  of  the  sea,  Christopher 
Columbus  in  the  course  of  his  first  voyage  of 
discovery  observed  coniferous  trees  and  palms 
associated  in  their  growth("').  This  gifted 
and  all-observing  man  speaks  of  the  circum- 
stance in  his  journal  as  a  singularity  ;  and  his 
friend  Anghiera,  secretary  to  Ferdinand  the 
Catholic,  says,  with  evident  astonishment^hat 
*'  in  the  newly  discovered  country  tl^iH^d 
palmeta  and  pineta  growing  togetheT^^Jis 
of  the  greatest  interest  in  a  geologica^^PPof 
view  to  contrast  the  present  distribution  of 
plants  upon  the  surface  of  the  earth  with  that 
which  the  floras  of  the  former  world  unfold  to 
us.  The  temperate  zone  of  the  southern  hem- 
isphere, abounding  in  water  and  in  islands,  and 
in  which  tropical  forms  of  vegetation  mingle  so 
strangely  with  the  forms  that  belong  to  colder 
regions  of  the  earth,  presents  us,  according  to 
Darwin's  beautiful,  animated  description,  witH 
the  most  instructive  examples  for  both  the  old 
and  the  new,  the  past  and  the  present  geogra- 
phy of  plants(^°*').  The  primeval  is  in  the 
strictest  sense  of  the  word  a  portion  of  the  his- 
tory of  phytology. 

The  Cycadeee,  which,  to  judge  by  the  num- 
ber of  species,  played  a  much  more  important 
part  in  the  world  that  has  passed  away  than  in 
that  which  now  exists,  accompany  the  allied 
Coniferae  from  the  epoch  of  the  coal  formation 
upwards.  They  are  almost  entirely  wanting 
in  the  period  of  the  variegated  sandstone,  in 
which  Coniferae  of  singular  formation  (Voltzia, 
Haidingera,  Albertia)  have  grown  luxuriantly  ; 
the  Cycadeae,  however,  attain  their  maximum 
in  the  Keuper  strata  and  the  lias,  where  about 
twenty  different  forms  make  their  appearance. 
In  the  chalk  the  prevailing  forms  are  those  of 
marine  and  fresh-water  plants  (Fuci  and  Na- 
jades).  The  cycadean  forests  of  the  Jura  for- 
mation have  by  this  time  been  long  exhausted, 
and  even  in  the  older  tertiary  formations  they 
remain  deep  behind  the  cone-bearing  tribes  and 
palms(3<'i). 

The  lignitic  or  brown-coal  strata,  which  are 
present  in  every  one  of  the  divisions  of  the 
tertiary  period,  amongst  the  earliest  forms  of 
cryptogamic  land  plants,  exhibit  a  few  palms, 
many  conifers  with  distinct  annual  rings,  and 
frondiferous  trees,  of  more  or  less  decided  trop- 
ical character.  In  the  middle  tertiary  period 
we  observe  the  complete  recurrence  of  the 
palms  and  cycadeans,  and  in  the  last  members 
of  this  epoch,  at  length,  strong  resemblances 
to  our  present  flora.  We  come  suddenly  upon 
our  pines  and  firs,  our  cupuliferous  tribes,  our 
planes,  and  our  poplars.  The  dicotyledonous 
stems  of  the  lignite  are  frequently  distinguish- 
ed by  gigantic  thic"kness  and  vast  age.  A  trunk 
was  found  near  Bonn,  in  which  Noggerath 
counted  792  annual  rings.  In  the  peat-moss 
of  the  Somme,  at  Yseux,  not  far  from  Abbe- 
ville, in  the  north  of  France,  oaks  have  been 
found  that  are  14  feet  in  diameter,  a  size  which, 
in  the  old  hemisphere,  is  very  remarkable  be- 
yond the  tropics(302).  Goeppert's  excellent  re- 
searches, which  it  is  hoped  will  soon  appear 
illustrated  with  plates,  inform  us,  "  that  all  the 
Baltic  amber  is  derived  from  a  coniferous  tree, 
which,  as  proclaimed  by  the  extant  remains  of 
the  wood  and  bark,  were  obviously  of  different 
ages,  came  nearest  to  our  white  and  red  pine 


timber,  but  still  constituted  a  particular  species. 
The  amber-tree  of  the  former  world  (Pinites 
succifer)  had  a  richness  in  resin  with  which 
none  of  the  coniferous  tribes  of  the  present 
world  will  bear  comparison,  inasmuch  as  great 
masses  of  amber  are  contained  not  only  within 
and  upon  the  bark,  but  also  between  the  rings 
of  the  wood  and  in  the  direction  of  the  medul- 
lary rays,  which,  as  well  as  the  cells,  are  seen 
under  the  microscope  to  be  filled  with  ambre- 
ous  resin  of  a  whiter  or  yellower  colour  in  dif- 
ferent places.  Amongst  the  vegetable  matters 
inclosed  in  amber  we  find  both  male  and  female 
flowers  of  indigenous,  acicular-leaved,  and  cu- 
puliferous trees  ;  but  distinct  fragments  of  Thu- 
ja, Cupressus,  Ephedera,  and  Castania  vesca, 
mingled  with  others  of  Junipers  and  Firs,  indi- 
cate a  vegetation  which  is  diflferent  from  that 
of  the  present  coasts  and  plains  of  the  BaUic 
Sea." 

In  the  geological  portion  of  our  Representa- 
tion of  Nature,  we  have  now  gone  over  the  whole 
series  of  formations,  from  the  oldest  eruptive 
rocks,  and  the  oldest  sedimentary  strata,  to  the 
newest  alluvium,  upon  which  lie  the  great  er- 
ratic blocks,  the  causes  or  means  of  whose  dis- 
tribution has  long  been  matter  of  discussion, 
but  which  for  my  own  part  I  am  less  disposed 
to  ascribe  to  icebergs,  than  to  the  eruption  and 
tumultuous  descent  of  great  masses  of  pent-up 
water  suddenly  let  loose  by  the  upheaval  of 
mountain  chains(2''3)  -pj^^  oldest  members  of 
the  transition  formation  with  which  we  are  ac- 
quainted, are  the  schists  and  greywacke,  which 
inclose  some  few  remains  of  seaweed  from  the 
Silurian,  formerly  the  Cambrian  Sea.  Upon 
what  did  these  oldest  rocks,  as  they  are  called, 
repose,  if  gneiss  and  mica-slate  are  to  be  re- 
garded but  as  metamorphosed  sedimentary 
strata  ]  Shall  we  venture  a  conjecture  in  re- 
gard to  that  which  cannot  be  the  object  of  ac- 
tual geological  observation  1  According  to  an 
ancient  Indian  Myth,  it  is  an  elephant  that  sup- 
ports the  earth  ;  and  the  elephant  himself,  that 
he  may  not  sink,  is  borne  by  a  gigantic  tortoise. 
Whereon  the  tortoise  stands,  it  is  not  allowed 
to  the  believing  Brahmin  to  inquire.  We  make 
bold  to  attempt  a  problem  of  the  sort,  although 
prepared  for  variety  of  blame  in  its  solution. 
On  the  first  formation  of  the  planets,  as  we 
have  made  it  probable  in  the  astronomical  por- 
tion of  our  Picture,  vaporous  rings  circulating 
about  the  sun  became  aggregated  into  spheres, 
and  gradually  consolidated  from  without  in- 
wards. What  we  call  the  older  Silurian  strata 
are  only  the  upper  portions  of  the  solid  crust 
of  the  earth.  The  eruptive  rocks  which  we  see 
breaking  through,  pushing  aside,  and  heaving 
up  these,  arise  from  depths  that  are  inaccessi- 
ble to  us ;  they  exist,  consequently,  under  the 
Silurian  strata,  composed  of  the  same  associa- 
tion of  minerals  which  are  familiar  to  us  under 
the  name  of  granite,  augite,  and  quartz-por- 
phyry, at  the  points  where,  by  breaking  through, 
they  become  visible.  Resting  on  analogies,  we 
may  safely  assume  that  that  which  at  one  and 
the  same  time  fills  extensive  fissures  in  the 
manner  of  veins,  and  bursts  through  the  sedi- 
mentary strata,  can  only  be  an  offset  from  an 
inferior  bed.  The  active  volcanoes  of  the  pres- 
ent day  carry  on  their  processes  at  the  greatest 


86 


GENERAL  PHYSICAL  GEOGRAPHY. 


depths  ;  and  from  the  strange  fragnaents  which 
I  have  found  included  in  streams  of  lava  in  dif- 
ferent quarters  of  the  globe,  I  also  hold  it  as 
more  than  probable  that  a  primogenial  granitic 
rock  is  the  foundation  of  the  great  systems  of 
stratification  which  are  filled  with  such  variety 
of  organic  remains(^°*).  If  basalts,  containing 
olivine,  first  make  their  appearance  in  the  cre- 
taceous period,  and  trachytes  show  themselves 
still  later,  the  eruptions  of  granite,  on  the  con- 
trary, belong  (as  metamorphic  productions  also 
assure  us)  to  the  epochs  of  the  oldest  sedi- 
mentary strata  of  the  transition  series.  Where 
knowledge  cannot  take  its  rise  from  the  imme- 
diate scrutiny  of  the  senses,  it  is  fairly  allow- 
able, even  on  grounds  of  pure  induction,  as  also 
after  a  careful  comparison  of  facts,  to  advance 
a  conjecture  which  restores  to  the  olden  gran- 
ite a  portion  of  its  threatened  rights,  and  its 
distinction  of  primordiahty. 

The  late  advances  of  geology,  the  extended 
knowledge  of  the  geological  epochs,  which  are 
characterized  by  the  mineralogical  diversity  of 
their  rocks  or  mineral  masses,  by  the  peculiar- 
ities and  succession  of  the  organic  remains 
which  they  contain,  by  the  position,  the  erec- 
tion or  the  undisturbed  horizontal  lie  of  the 
strata,  all  these  considerations  lead  us,  follow- 
ing the  intimate  causal  connection  of  phenom- 
ena, to  the  division,  in  respect  of  space,  of  the 
solid  and  the  fluid,  of  the  continents  and  the 
seas  which  constitute  the  surface  of  our  planet. 
And  here  we  indicate  a  point  of  union  between 
that  which  is  historical  in  geology  with  refer- 
ence to  the  earth — cosmographical  geology,  and 
geographical  geology,  or  the  general  considera- 
tion of  the  form  and  partition  of  continents. 
The  limitation  of  the  Solid  by  the  Fluid,  and 
the  relations  in  respect  of  area  between  the  one 
and  the  other,  have  been  very  different  at  dif- 
ferent times  in  the  long  succession  of  geologi- 
cal epochs,  according  as  the  sedimentary  car- 
boniferous strata  were  deposited  horizontally 
on  the  upright  strata  of  mountain  lime-  and  old 
red  sand  stone  ;  as  lias  and  oolite  were  laid  on 
banks  of  kuper  and  muschelkalk  ;  and  as  chalk 
was  accumulated  on  the  acclivities  of  the  green 
sand  and  Jura  limestone.  If,  with  M.  Elie  de 
Beaumont,  we  designate  the  waters  under 
which  the  Jura  limestone  and  the  chalk  were 
precipitated  in  the  shape  of  mud  or  slime,  as 
the  Jurassic  and  cretaceous  seas,  then  will  the 
contour  of  the  two  formations  just  mentioned 
give  us  the  boundary  for  two  epochs,  between 
the  ocean  still  engaged  in  forming  rocks,  and 
the  land  already  laid  dry.  The  happy  idea  has 
even  been  conceived  of  forming  maps  of  these 
physical  elements  of  primeval  geography  ;  and 
these  maps  are  perhaps  more  accurate  than 
those  which  have  been  composed  in  illustration 
of  the  wanderings  of  lo  and  the  Homeric  narra- 
tives. The  latter  give  graphic  representations 
of  opinions  and  mythical  images ;  the  former  ex- 
hibit facts  in  the  positive  science  of  formation. 

The  result  of  investigations  into  the  extent 
of  exposed  area,  or  dry  land,  is  this  :  that  in 
the  earliest  times,  in  the  Silurian  or  Devonian 
transition  epochs,  as  also  in  the  first  floetz  pe- 
riod, throughout  its  tripartite  division,  the  dry 
land,  the  surface  occupied  by  land  plants,  was 
limited  to  separate  islands ;  that  these  islands 


united  at  later  epochs,  and  inclosed  numerons 
inland  lakes  by  the  sides  of  deeply-indented 
bays  of  the  sea  ;  that  finally,  when  the  mount- 
ain chains  of  the  Pyrenees  and  Apennines  and 
Carpathians  arose — towards  the  time  of  the 
older  tertiary  strata,  therefore — extensive  con- 
tinents, having  almost  the  dimensions  of  those 
of  th^^esent  day,  had  appeared.  In  the  times 
of  y^BJttjrian  world,  as  well  as  in  the  epoch 
of  ^^^Hhest  luxuriance  of  the  Cycadeae  and 
gigaflPPcaurians,  the  quantity  of  dry  land  from 
pole  to  pole  might  very  possibly  have  been 
even  less  than  it  is  in  the  Pacific  and  Indian 
Oceans  at  the  present  time.  How  this  prepon- 
derating mass  of  water,  in  common  with  other 
causes,  conduced  to  elevation  of  temperature, 
and  to  greater  equalityof  climate,  will  be  the 
subject  of  consideration  by  and  by.  Here  it 
n^ust  only  be  farther  remarked,  in  considering 
the  gradual  augmentation  (agglutination)  of  the 
uplifted  dry  land,  that  shortly  before  the  revo- 
lutions, which,  after  shorter  or  longer  pauses 
in  the  diluvial  period,  occasioned  the  sudden 
extinction  of  so  many  gigantic  vertebrate  ani- 
mals, portions  of  the  present  continental  mass- 
es were  still  completely  separate  from  one  an- 
other. In  South  America  and  the  Australasian 
lands,  there  is  a  great  prevailing  resemblance 
between  the  existing  animals  and  those  that 
have  become  extinct.  In  New  Holland,  the 
fossil  remains  of  kangaroos  have  been  discov- 
ered, and  in  New  Zealand  the  semifossil  bones 
of  a  gigantic  struthious  bird,  Owen's  Dinornis, 
closely  allied  to  the  existing  Apterix,  but  hav- 
ing little  affinity  to  the  so  lately  extinguished 
Dronte  or  Dodo  of  the  island  of  Rodriguez. 

The  outline  of  former  continents  was  perhaps 
indebted  in  principal  measure  for  its  elevation 
above  the  surrounding  sea-level  to  the  eruption 
of  quartzose  porphyry,  an  event  which  so  pow- 
erfully shook  the  first  great  vegetable  covering 
of  the  dry  land,  from  which  were  derived  the 
materials  of  the  coal  measures.  What  we  call 
plains  or  flats  (in  continents),  are  no  more  than 
the  broad  backs  of  hills  and  mountains  whose 
feet  are  at  the  bottom  of  the  sea.  Each  plain, 
in  its  submarine  relations,  is,  in  fact,  a  lofty 
plateau  or  table-land,  whose  inequalities  have 
been  concealed  by  new  sedimentary  deposi- 
tions in  horizontal  beds,  as  well  as  by  alluviums 
spread  over  its  surface  by  floods. 

Among  the  general  considerations  which  be- 
long to  a  Picture  of  Nature,  the  foremost  place 
must  be  given  to  the  quantity  of  terra  fir  ma 
projecting,  uplifting  itself  above  the  level  of  the 
sea  ;  such  a  determination  of  continental  areas 
includes  the  consideration  of  their  individual 
forms  in  point  of  horizontal  extension  (seg- 
mentary relations),  and  of  perpendicular  eleva- 
tion (the  hypsometrical  relations  of  mountain 
chains).  Our  planet  has  two  coverings  or  en- 
velopes :  one  general,  the  Atmosphere,  as  elastic 
fluid,  and  one  particular,  only  locally  distributed, 
bounding  the  Solid,  and  thereby  givmg  it  its 
figure,  the  Sea.  These  two  coverings,  the  air 
and  the  ocean,  form  a  natural  whole  which 
gives  the  surface  of  the  earth  its  climate,  di- 
verse according  to  'the  relative  extent  of  the 
sea  and  of  the  land,  of  the  division  and  geo- 
graphical position  of  the  land,  and  of  the  direc- 
tion and  elevation  of  its  mountain  chains. 


PHYSICAL  GEOGRAPHY— THE  LAND. 


87 


From  this  knowledge  of  the  reciprocal  influ- 
ences of  the  air,  ocean,  and  land  it  appears  that 
great  meteorological  phenomena,  severed  from 
geological  considerations,  cannot  be  under- 
stood. Meteorology,  like  the  geography  of 
plants  and  animals,  first  began  to  make  some 
progress  since  observers  have  become  persua- 
ded of  the  mutual  interdependence  of  the  phe- 
nomena to  be  investigated.  The  word  Climate 
implies  in  the  first  instance  a  specific  constitu- 
tion of  the  atmosphere ;  but  this  constitution 
depends  on  the  ceaseless  reciprocal  influences 
exerted  between  an  ever  and  deeply-agitated 
ocean,  crossed  in  different  directions  by  cur- 
rents of  totally  dissimilar  temperatures,  and 
the  heat-radiating  dry  land,  variously  partition- 
ed, elevated,  coloured,  naked  or  covered  with 
lofty  trees  or  lowly  herbs. 

In  the  present  condition  of  the  surface  of 
our  planet,  the  area  of  the  dry  to  that  of  the 
fluid  is  as  1  :  2| ;  according  to  Rigaud(3''*),  as 
100  :  270.  The  islands  form  at  present  scarcely 
■5^3  of  the  continental  masses.  The  latter  are 
so  unequally  divided,  that  in  the  northern  hem- 
isphere they  offer  a  three  times  greater  extent 
of  surface  than  they  do  in  the  southern  hemi- 
sphere. The  southern  hemisphere  is  conse- 
quently most  especially  oceanic  in  its  prevail- 
ing character.  From  40°  S.  latitude  on  towards 
the  antartic  pole,  the  crust  of  the  earth  is  al- 
most entirely  covered  with  water.  Even  as 
predominating,  and  only  broken  here  and  there 
by  insignificant  clusters  of  islands,  is  the  fluid 
element  between  the  east  coasts  of  the  Old  and 
the  west  coasts  of  the  New  World.  The  learn- 
ed hydrographer,  Fleurieu,  by  way  of  distin- 
guishing this  extensive  sea  basin  from  other 
seas,  has  very  well  entitled  it  the  Great  Ocean. 
Within  the  tropics  it  includes  a  breadth  of  as 
many  as  145  degrees  of  longitude.  The  south- 
ern and  western  hemispheres,  beginning  the 
reckoning  from  the  meridian  of  Teneriffe,  are 
thus  the  regions  of  the  earth's  surface  that 
most  abound  in  water. 

These  are  the  principal  points  in  the  consid- 
eration of  the  relative  quantities  of  the  land 
and  sea,  a  relation  which  exerts  so  vast  an  in- 
fl^uence  upon  the  distribution  of  temperature ; 
the  variation  of  atmospheric  pressure  ;  the  di- 
rection of  winds,  and  the  hygrometric  state  of 
the  air  which  particularly  and  so  essentially 
determines  the  force  of  vegetation.  When  we 
think  that  nearly  three-fourths  of  the  surface 
of  the  earth  are  covered  with  water(^°*),  we  are 
less  astonished  at  the  imperfect  state  of  me- 
teorology up  to  the  commencement  of  the  pres- 
ent century — an  epoch  when  a  considerable 
mass  of  accurate  observations  on  the  tempera- 
ture of  the  sea,  under  different  parallels  of  lat- 
itude and  at  different  seasons  of  the  year,  was 
first  obtained  and  numerically  contrasted. 

The  horiz(mtal  figure  of  the  land,  in  its  most 
general  relations  of  extension,  was  already  an 
object  of  ingenious  consideration  at  an  early 
period  in  the  history  of  the  Greek  civilization. 
It  was  sought  to  ascertain  the  greatest  exten- 
sion from  east  to  west,  and  Dicearchus,  ac- 
cording to  the  testimony  of  Agathemeriis,  found 
this  to  lie  in  the  latitude  of  Rhodes  in  a  direc- 
tion from  the  Pillars  of  Hercules  to  Thinae. 
This  is  the  line  which  was  called  the  Parallel 
of  the  Diaphragm  of  Dicearchus,  the  astronom- 


ical accuracy  of  whose  position  (which  I  have 
myself  examined  in  another  place)  must  ever 
be  the  subject  of  admiration(^°^).  Strabo,  led 
apparently  by  Eratosthenes,  appears  to  have 
been  so  thoroughly  persuaded  that  as  this  par- 
allel of  36°,  the  maximum  extension  of  the 
world,  as  known  to  him,  was  intimately  con- 
nected with  the  figure  of  the  earth,  fliat  he  fixes 
the  place  of  the  continent  which  he  prophesied 
must  exist  in  the  northern  hemisphere,  between 
Iberia  ami  the  coast  of  Thinae,  as  also  falling 
under  the  same  degree  of  latitudeC^""*). 

If,  as  already  remarked,  considerably  more 
land  has  been  raised  above  the  level  of  the  sea 
in  the  one  hemisphere  than  in  the  other— and 
this  is  the  case  vi^hether  the  globe  be  halved  in 
the  line  of  the  equator,  or  in  that  of  the  merid- 
ian of  Teneriffe — the  two  great  masses  of  land, 
true  islands  surrounded  by  the  sea  on  every 
side,  which  we  designate  the  Eastern  and  West- 
ern continents,  the  Old  and  New  Worlds,  be- 
side the  most  striking  contrasts  in  configura- 
tion at  large,  or  rather  in  the  position  of  their 
greater  axes,  still  present  many  points  of  re- 
semblance in  the  details  of  their  configuration, 
particularly  in  the  extent  and  outline  of  their 
opposite  coasts.  In  the  Eastern  division,  the 
prevailing  direction  or  position  of  the  longer 
axis  is  from  east  to  west  (more  correctly,  from 
south-west  to  north-east) ;  in  the  Western  con- 
tinent, however,  it  is  meridional,  or  from  north 
to  south  (more  accurately,  from  south-south- 
east to  north-north-west).  Both  masses  are  cut 
off  towards  the  north  in  the  line  of  the  same  par- 
allel of  latitude — generally  in  that  of  70°  ;  and 
to  the  south  they  both  run  out  into  pyramidal 
points,  which  have  mostly  a  submarine  exten- 
sion in  the  shape  of  islands  and  shoals.  This 
is  proclaimed  by  the  archipelago  of  Terra  del 
Fuego  ;  the  Lagullas  bank,  to  the  south  of  the 
Cape  of  Good  Hope,  and  Van  Diemen's  Land, 
separated  from  New  Holland  by  the  Bass 
Straits.  The  Northern  Asiatic  coast  exceeds, 
or  runs  up  beyond  the  parallel  of  70°  mention- 
ed above,  about  Cape  Taimura  (78°  16'  N,  lat. 
according  to  Kreusenstern),  whilst  from  about 
the  embouchure  of  the  great  Tschoukotschja 
river  eastward,  in  the  direction  of  Behrrng's 
Straits,  the  north-eastern  promontories  of  Asia 
(Cook's  East-Cape)  do  not  reach  higher  than 
66°  3'  according  to  Beechey(30').  The  north- 
ern shore  of  the  New  Continent  follows  the 
70th  parallel  pretty  closely  ;  as  both  south  and 
north  of  Barrow's  Straits,  from  Boothia-felix 
and  Victoria-land,  all  the  land  consists  only  of 
detached  islands. 

The  pyramidal  figure  of  all  the  southern  ter- 
minations of  continents  belongs  to  the  "  Simil- 
itudines  physicae  in  configuratione  mundi,"  to 
which  Bacon  had  already  directed  attention  in 
the  Novum  Organum,  and  with  which  Cook's 
companion  in  his  second  voyage  round  the 
world,  Reinhold  Forster,  has  connected  some 
very  acute  and  interesting  considerations.  Pro- 
ceeding from  the  meridian  of  the  Island  of  Ten- 
erifl!e  eastward,  we  observe  the  southern  ex- 
tremities of  three  great  continents,  namely,  of 
Africa  (the  extreme  of  the  old  world),  Austra- 
lia, and  South  America,  approaching  the  south- 
pole  successively  nearer  and  nearer.  New  Zea- 
land, which  is  fully  twelve  degrees  of  latitude 
in  length,  forms  a  very  regular  intermediate 


88 


PHYSICAL  GEOGRAPHY— THE  LAND. 


member  lying  between  Australia  and  South 
America,  and  also  ending  with  an  island — New 
Leinster — to  the  south.  Another  remarkable 
feature  in  the  configuration  of  our  present  con- 
tinents is  this :  that  almost  under  the  same 
meridians  under  which  the  most  southern 
stretches  of  the  land  are  made,  the  northern 
coasts  alsolhoot  out  and  reach  the  highest  lat- 
itudes towards  the  arctic  pole.  This  appears 
on  comparing  the  Cape  of  Good  Hope  and  the 
Lagullas  bank  with  the  North  Cape,  and  the 
peninsula  of  Malacca  with  Cape  Taimura  in 
Siberia(3^'').  Whether  the  poles  are  girded 
with  terra  firma,  or  surrounded  by  an  ocean 
covered  with  horizontal  strata  of  ice  (consoli- 
dated water),  we  know  not.  The  North-pole 
has  been  approached  as  high  as  82°  55'  N.  lat- 
itude ;  the  South-pole  not  higher  than  78°  10' 
S.  latitude. 

In  the  same  way  as  the  great  continental 
masses  terminate  pyramidally  towards  the 
south,  the  like  configuration  is  variously  and 
almost  everywhere  repeated  on  a  smaller  scale, 
not  only  in  the  great  Indian  Ocean  (the  penin- 
sulas of  Arabia,  Hindostan,  and  Malacca),  but 
also,  as  observed  by  Eratosthenes  and  Polybi- 
us,  in  the  Mediterranean,  where  the  Iherian, 
Italian,  and  Hellenic  peninsulas  present  corre- 
sponding sensible  configurations(3").  Europe, 
with  an  area  of  but  one-fifth  that  of  Asia,  is  in 
like  manner  but  a  western,  many-membered 
peninsula  of  the  Asiatic  and  almost  undivided 
portion  of  the  globe ;  and  the  climatic  peculi- 
arities of  Europe  also  show  that  it  stands  to 
Asia  very  much  in  the  same  relationship  as 
the  peninsula  of  Brittany  does  to  the  rest  of 
France(3'2).  The  influence  which  the  subdi- 
visions of  a  continent,  the  higher  development 
of  its  form,  exerts  at  once  upon  the  manners 
and  whole  civilization  of  a  people,  is  obviously 
particularly  alluded  to  by  Strabo(3"),  when  he 
commends  the  "greatly  diversified  form"  of 
our  small  division  of  the  globe,  as  an  especial 
advantage.  Africa(^^*)  and  South  America, 
which  in  other  respects  exhibit  such  similari- 
ties in  their  configuration,  are  those  among  the 
great  masses  of  land  which  have  the  simplest 
outhnes  of  coast.  It  is  only  the  eastern  sea- 
board of  Asia,  broken  in  upon  by  the  currents 
of  the  east  sea  (fractas  ex  aequore  terras),  that 
shows  variety  and  irregularity  of  outline(2^^). 
Peninsulas  and  a  succession  of  islands  there 
alternate  from  the  equator  to  60°  of  N.  latitude. 

Our  Atlantic  Ocean  bears  every  feature  of 
a  great  valley.  It  is  as  if  floods  had  directed 
their  shocks  successively  to  the  north-east, 
then  to  the  north-west,  and  then  to  the  north- 
east again.  The  parallelism  of  the  opposite 
coasts  northward  from  10°  of  S.  latitude,  their 
advancing  and  retreating  angles,  the  convexity 
of  the  shores  of  Brazil  opposite  those  of  the 
Gulf  of  Guinea,  the  convexity  of  Africa  under 
the  same  parallels  of  latitude  as  the  deep  inden- 
tation formed  by  the  Gulf  of  Mexico,  all  vouch 
for  this  apparently  bold  view(3»6).  In  this  Atlan- 
tic valley,  as  almost  everywhere  else  in  the 
configuration  of  great  masses  of  land,  indented 
and  isle-studded  shores  stand  opposite  to  unin- 
dented  coasts.  It  is  long  since  I  directed  at- 
tention to  the  circumstance  how  remarkable  in 
a  geological  point  of  view  was  the  comparison 
of  the  west  coasts  of  Africa  and  South  Amer- 


ica within  the  tropics.  The  deep  bay-like  in- 
ward sweep  of  the  African  coast  by  Fernando 
Po  (4^°  N.  lat.),  is  repeated  on  the  American 
continent  under  18 J °  S.  lat.  at  the  tropical 
point  near  Arica,  where  (between  the  Valle  de 
Arica  and  the  Morro  de  Juan  Diaz)  the  Peru- 
vian coast  suddenly  changes  its  course  from 
south  to  north  into  a  north-western  direction. 
This  change  of  direction  extends  in  like  meas- 
ure to  the  lofty  chain  of  the  Andes,  which  here 
proceeds  in  two  parallel  connected  lines ;  and 
not  only  to  the  lofty  plateaus  near  the  coast(3^^), 
but  also  to  the  eastern  plains,  the  earliest  seat 
of  human  civilization  in  the  South  American 
continent,  where  the  little  alpine  lake  of  Titi- 
caca  is  bounded  by  the  colossal  mountains, 
Sorata  and  Illimani.  Farther  towards  the  south, 
from  Valdivia  and  Chiloe  (40'^  to  42°  S.  lat.), 
through  the  Archipelago  de  los  Chonos  on  to 
the  Terra  del  Fuego,  the  curious  Fiord-forma- 
tion, the  complication  of  narrow,  deeply-pene- 
trating bays  or  arms  of  the  sea,  is  repeated, 
which,  in  the  northern  hemisphere,  we  find 
characterizing  the  west  coasts  of  Norway  and 
of  Scotland. 

Such  are  the  most  general  considerations 
that  suggest  themselves  on  the  configuration  of 
continents  (the  extension  of  the  dry  land  in  a 
horizontal  direction),  as  a  survey  of  the  surface 
of  our  planet  offers  them  at  the  present  time. 
We  have  here  placed  facts  in  juxtaposition, 
analogies  in  form  occurring  in  remote  districts 
of  the  earth,  which,  however,  we  do  not  ven- 
ture to  speak  of  as  Laws  of  Form.  When  on 
the  flanks  of  a  still  active  volcano,  of  Vesuvius 
for  example,  we  observe  the  not  uncommon 
phenomenon  of  partial  upheavings  of  the  soil, 
in  which  small  portions  of  the  solid  earth, 
either  before  or  in  the  course  of  an  eruption, 
permanently  change  their  level  by  several  feet, 
and  rise  in  penthouse-like  ridges  or  flat  eleva- 
tions, we  perceive  how  it  must  depend  on  tri- 
fling accidents  of  intensity  in  the  force  of  sub- 
terraneous vapours,  and  in  the  amount  of  re- 
sistance to  be  overcome,  that  the  upheaved 
parts  assume  this  or  that  form  and  direction. 
Even  so  may  slight  disturbances  of  the  equi- 
librium in  the  interior  of  our  planet  have  deter- 
mined the  upheaving  elastic  forces  to  operate 
towards  the  Northern  in  a  greater  degree  than 
towards  the  Southern  hemisphere ;  to  throw 
up  the  Eastern  hemisphere  as  a  broad  continu- 
ous mass  with  its  principal  axis  running  nearly 
parallel  to  the  equator,  the  Western  and  more 
oceanic  hemisphere,  again,  as  a  narrower  band, 
with  its  axis  nearly  in  the  plane  of  the  meridian. 

On  the  aetiological  connection  of  such  grand 
incidents  in  the  production  of  the  dry  land,  of 
similarity  and  contrast  i:\.  the  configuration  of 
continents,  there  is  little  to  be  made  out  em- 
pirically. We  only  know  one  thing  :  that  the 
efficient  cause  is  subterraneous  ;  that  the  pres- 
ent fashion  of  continents  and  islands  has  not 
been  obtained  at  once  ;  but,  as  has  been  al- 
ready observed,  that  from  the  epoch  of  the  Si- 
lurian formation  (Neptunian  separation),  on  to 
that  of  the  tertiary  deposits,  there  have  been 
many  alternate  elevations  and  depressions  of 
the  surface,  which,  on  the  whole,  has  gradually 
increased  in  extent,  and,  from  numerous  small- 
er  divisions,  has   coalesced  into   the   larger 


PHYSICAL  GEOGRAPHY— THE  LAND. 


masses  which  we  now  behold.  The  present 
configuration  is  the  product  of  two  causes, 
which  exerted  their  influence  in  succession, 
one  after  another  :  firstly,  a  subterraneous 
manifestation  offeree,  whose  measure  and  di- 
rection we  call  accidental,  because  we  have  no 
means  of  determining  them ;  because,  to  our 
understanding,  they  are  abstracted  from  the 
circle  of  necessity ;  secondly,  powers  that  are 
efficient  on  the  surface,  among  which,  volcanic 
eruptions,  earthquakes,  the  upheaval  of  mount- 
ain chains,  and  ocean  currents,  have  played  the 
principal  part.  How  totally  different  would 
have  been  the  state  of  the  earth,  in  reference 
to  temperature,  and,  along  with  this,  how  dis- 
similar the  state  of  vegetation,  of  agriculture, 
and  of  human  society,  had  the  principal  axis 
of  the  new  continent  lain  in  the  same  direction 
as  that  of  the  old — had  the  Andes,  instead  of 
being  uplifted  in  the  plane  of  the  meridian,  been 
raised  from  east  to  west — had  there  been  no 
extensive  tropical  land  radiating  heat  to  the 
south  of  Europe  (Africa) — had  the  Mediterra- 
«  nean,  which  once  communicated  and  made  one 
with  the  Caspian  and  Red  seas,  and  has  proved 
so  essential  a  means  in  promoting  the  civiliza- 
tion of  mankind,  had  no  existence — had  its  bot- 
tom been  raised  to  the  same  level  as  the  plains 
of  Lombardy  and  Cyrene  ! 

The  alterations  in  the  respective  levels  of 
the  solid  and  fluid  portions,  of  the  earth's  sur- 
face— alterations  which,  at  one  and  the  same 
time,  determine  the  outlines  of  continents,  and 
leave  dry  or  overflow  districts  of  low-lying 
land,  are  to  be  ascribed  to  a  variety  of  causes 
operating  at  different  times.  The  most  pow- 
erful have  unquestionably  been  :  the  force  of 
elastic  vapours,  which  the  interior  of  the  earth 
encloses  :  the  sudden  change  of  temperature  of 
great  mountain  chainsc^^**) ;  the  unequal  secu- 
lar loss  of  heat  by  the  crust  and  core  of  the 
earth,  which  has  occasioned  the  wrinklings  or 
zigzag  foldings  conspicuous  on  many  occasions 
in  the  solid  surface  ;  local  modifications  of  the 
force  of  gravitation(3i9),  and,  as  a  consequence 
of  these,  altered  curvature  of  a  portion  of  the 
fluid  element. 

That  the  elevation  of  continents  has  been  an 
actual,  not  a  seeming  one  only,  attributable  to 
the  form  of  the  surface  of  the  sea,  appears  to 
follow  from  views  now  adopted  by  geologists 
generally,  and  from  the  long  observation  of 
connected  facts,  as  well  as  from  the  analogy 
of  the  more  important  volcanic  phenomena. 
The  merit  of  this  view  also  belongs  to  Leopold 
von  Buch,  who  announced  it  in  the  account  of 
his  remarkable  travels  through  Norway  and 
Sweden,  in  the  years  1806  and  1807,  when  it 
was  first  introduced  to  science(320).  Whilst 
the  whole  of  the  coasts  of  Sweden  and  Finland, 
from  the  limits  of  north  Scania  (Solvitsborg), 
through  Gefle,  to  Torneo,  and  from  Torneo  to 
Abo,  is  rising  (the  rise,  in  the  course  of  a  cen- 
tury, amounts  to  four  feet),  south  Sweden,  on 
the  contrary,  according  to  Nilson,  is  sinking(32i). 
The  maximum  of  the  upheaving  power  appears 
to  lie  in  north  Lapland.  The  upheaval  falls  off 
gradually  towards  the  south  as  far  as  Calmar 
and  Solvitsborg.  Lines  of  what  were  old  sea-lev- 
els within  historical  times,  are  indicated  along 
the  coasts  of  the  whole  of  Norway,  from  Cape 
Lindesnaes  to  the  extreme  north  Cape,  by  beds 
M 


of  shells  of  the  present  ocean("='),  and  have  late- 
ly been  most  accurately  measured  by  Bravais, 
during  the  long  winter  residence  at  Bosekop. 
These  shores  lie  as  many  as  600  feet  above 
the  present  mean  sea-level,  and,  according  to 
Keilhau  and  Eugenius  Robert,  the  same  thing 
extends  nor-nor-west  to  the  coasts  of  Spitzber- 
gen,  opposite  the  North-cape.  Leopold  von 
Buch,  who  was  the  first  to  direct  attention  to 
the  raised  bed  of  shells  near  Tromsoe  (69=*  40' 
N.  lat.),  has,  however,  shown  that  the  old  up- 
heavals along  the  line  of  the  North  Sea  be- 
long to  another  class  of  phenomena  than  the 
smooth  and  gradual  rising  of  the  Swedish  coasts 
of  the  Gulf  of  Bothnia.  The  last  phenomenon, 
vouched  for  by  sure  historical  testimony,  must 
not,  therefore,  be  confounded  with  that  altera- 
tion in  the  level  of  the  surface  which  accom- 
panies earthquakes,  as  in  the  case  of  the  coasts 
of  Chili  and  of  Cutch.  It  has  very  recently 
given  occasion  to  precisely  similar  observa- 
tions in  other  countries.  To  the  rising  there 
occasionally  corresponds,  as  a  consequence  of 
the  folding  of  strata,  an  obvious  sinking,  as 
in  West-(jreenland  (according  to  Pingel  and 
Graah),  in  Dalmatia  and  in  Scania. 

If  we  regard  it  as  extremely  probable,  that 
in  the  earlier  ages  of  our  planet  the  oscillating 
movements  of  the  soil,  the  alternate  elevations 
and  depressions  of  the  surface,  were  greater 
than  they  are  at  present,  we  shall  be  less  sur- 
prised at  finding  single  spots  on  the  face  of  the 
globe,  in  the  interiors  of  continents,  that  lie 
deeper  than  the  present  uniform  level  of  the 
ocean.  Examples  of  this  kind  are  presented 
by  the  Natron  lakes,  described  by  General  An- 
dreossy,  the  small  bitter  lakes  of  the  Isthmus 
of  Suez,  the  Caspian  Sea,  the  Sea  of  Tiberias, 
and,  above  all,  the  Dead  Sea(323).  The  level 
of  the  Sea  of  Tiberias  is  625  feet,  and  that  of 
the  Dead  Sea  no  fewer  than  1230  feet  lower 
than  that  of  the  Mediterranean  mirror.  Could 
the  drift  and  alluvium  that  cover  the  rocky 
strata  in  so  many  parts  of  the  earth  be  all  at 
once  removed,  it  would  then  be  obvious  how 
much  of  the  rocky  foundation  lies  actually  low- 
er than  the  present  sea  level.  The  periodical, 
although  irregular,  alternate  rise  and  fall  in 
the  waters  of  the  Caspian  Sea,  of  which  I  have 
myself  seen  unquestionable  traces  in  the  nor- 
thern parts  of  this  basin(^^*),  appear,  like  the 
observations  of  Darwin  in  the  Coral  Ocean("^), 
to  proclaim,  that  without  any  proper  shock  or 
concussion,  the  surface  of  the  earth  is  still 
susceptible  of  the  same  smooth  and  progress- 
ive undulations  which  in  primeval  times,  and 
when  the  thickness  of  the  consolidated  crust 
was  much  less  than  it  is  at  present,  were  much 
more  general  [and  extensive]  than  they  are 
now. 

The  phenomena  to  which  we  here  direct  at- 
tention remind  us  of  the  instability  of  the  pres- 
ent order  of  things,  in  the  changes  which,  at 
far  distant  intervals  of  time,  the  outline  and 
configuration  of  continents  have  in  all  proba- 
bility undergone.  Incidents  that  are  scarcely 
recognizable  to  successive  generations  of  men, 
accumulate  in  periods  of  the  length  of  which 
the  movements  of  the  heavenly  bodies  supply 
the  measure.  In  the  course  of  8000  years  the 
east  coast  of  the  Scandinavian  peninsula  has  ris- 
en to  the  extent  perhaps  of  about  320  feet ;  after 


PHYSICAL  GEOGRAPHY— THE  LAND. 


the  lapse  of  12,000,  if  the  motion  prove  contin- 
uous and  equable,  parts  of  the  bottom  of  the 
ocean  that  lie  near  the  peninsula,  and  at  the 
present  day  are  covered  with  100  feet  of  wa- 
ter, and  more,  will  have  come  to  the  surface, 
and  begun  to  be  laid  dry.  But  what  is  the 
brevity  of  these  intervals  compared  with  the 
length  of  the  geological  periods,  which  the  suc- 
cession of  strata  in  the  several  formations, 
and  the  host  of  extinct  and  totally  different  or- 
ganisms which  they  inclose,  reveal  to  us  !  We 
have  here  considered  the  phenomenon  of  up- 
heavement  only ;  but  we  can  readily,  resting 
on  the  analogies  of  facts  observed,  in  like  meas- 
ure figure  to  ourselves  the  possibility  of  the 
sinking  or  submersion  of  whole  districts  of 
country.  The  mean  height  of  the  level,  or 
non-mountainous  portions  of  France  is  not 
quite  480  feet.  Contrasted  with  former  geo- 
logical periods,  in  which  more  extensive  chan- 
ges went  on  in  the  interior  of  the  earth,  we 
perceive  that  no  very  long  period  of  time  were 
requisite  to  have  considerable  portions  of  the 
north-west  of  Europe  permanently  overflowed, 
and  presenting  in  its  sea-board  a  very  different 
outline  from  that  which  now  distinguishes  it. 

Risings  and  fallings  of  the  solid,  or  of  the  fluid 
— in  their  several  effects  so  evenly  balanced 
that  the  rise  of  the  one  occasions  the  seeming 
fall  of  the  other — are  the  cause  of  every  change 
in  the  configuration  of  continents.  In  a  gener- 
al Picture  of  Nature,  in  a  liberal,  not  one-sided, 
presentment  of  the  phenomena  of  nature,  the 
possibility  at  least  of  a  diminution  in  the  mass 
of  waters,  of  a  true  sinking  in  the  mean  sea- 
level,  must  therefore  be  indicated.  That  with 
the  former  high  temperature  of  the  surface  of 
the  earth,  with  the  greater  water-engulfing 
fissuration  of  its  crust,  with  a  totally  different 
constitution  of  its  surrounding  atmosphere, 
great  variations  in  the  level  of  the  sea  may 
have  taken  place  in  connection  with  the  in- 
crease or  decrease  of  the  liquid  element,  there 
is  no  room  left  for  doubt.  In  the  actual  condi- 
tion of  our  planet,  however,  we  are  totally  with- 
out any  direct  evidence  of  an  actual  progressive 
decrease  or  increase  of  the  sea ;  we  are  also 
without  any  proof  of  change  in  the  mean  height 
of  the  barometer  at  the  sea  level  of  the  same 
points  of  observation.  From  Daussy's  and  An- 
tonio Nobile's  researches,  it  appears  that  an  in- 
crease in  the  height  of  the  barometer  would  of 
itself  be  accompanied  with  a  depression  of  the 
sea-level.  But  as  the  mean  pressure  of  the  at- 
mosphere at  the  level  of  the  sea,  in  consequence 
of  meteorological  causes — direction  of  the  wind, 
moistness  of  the  air — is  not  the  same  under  ev- 
ery parallel  of  latitude,  the  barometer  of  itself 
can  supply  no  certain  evidence  of  change  in  the 
liquid  level  of  our  globe.  The  remarkable  phe- 
nomenon which  was  observed  in  the  beginning 
of  the  present  century,  when  several  harbours 
of  the  Mediterranean  were  repeatedly  left  com- 
pletely dry  for  many  hours,  appears  to  indicate 
that  alterations  in  the  direction  and  strength 
of  currents,  without  any  actual  diminution  in 
the  quantity  of  water,  without  any  general  de- 
pression of  the  level  of  the  ocean,  may  give 
rise  to  local  recessions  of  its  waters,  and  to 
permanent  exposures  of  small  portions  of  its 
shores.  From  the  knowledge  lately  obtained 
of  these  complicated  phenomena,  it  seems  that 


we  must  be  particularly  cautious  in  interpret- 
ing them,  inasmuch  as  effects  may  very  readily 
be  ascribed  to  one  of  the  "  old  elements,"  the 
water,  which  belong  of  right,  and  in  fact,  to 
two  others,  the  earth  and  the  air. 

As  continents,  which  we  have  hitherto  delin- 
eated in  their  horizontal  extension,  by  their 
configuration,  by  their  external  distribution  and 
their  variously  indented  coasts,  exert  a  benefi- 
cial influence  upon  climate,  commerce,  and  the 
progress  of  civilization,  so  is  there  another  kind 
of  internal  subdivision  effected  by  perpendicu- 
lar elevations  of  the  surface  —  by  mountain 
chains  and  lofty  table  lands — which  have  con- 
sequences that  are  not  less  important.  All 
that  occasions  change,  variety  of  form  and  fea- 
ture, in  the  surface  of  the  planet — the  dwell- 
ing-place of  the  human  family — besides  mount- 
ain chains,  great  lakes,  grassy  steppes,  and 
even  deserts  surrounded  by  wooded  regions  as 
by  coasts,  impresses  a  peculiar  character  on 
communities.  Lofty  ridges  covered  with  snow 
interrupt  communication,  interfere  with  traffic  ; 
but  a  mixture  of  less  elevated  mountain  mem- 
bers lying  apart(3'**),  and  of  low  lands,  such  as 
the  West  and  South  of  Europe,  present  in  such 
happy  interchange,  occasion  variety  in  the  me- 
teorological processes,  as  well  as  in  the  prod- 
ucts of  the  vegetable  kini^dom  ;  and  further  be- 
get wants,  as  every  district  even  under  the 
same  degree  of  latitude  then  falls  under  the 
dominion  of  a  different  kind  of  husbandry,  the 
satisfaction  of  which  arouses  the  activity  of  the 
inhabitants.  Thus  have  the  dreadful  convul- 
sions that  have  ensued  upon  the  reactions  of 
the  interior  against  the  exterior,  upon  sudden 
upheavals  of  portions  of  the  oxidized  crust  of 
the  earth,  upon  the  elevation  of  vast  mountain 
chains,  still  proved  conducive,  with  tranquillity 
restored,  with  the  revival  of  the  slumbering 
might  of  the  organizing  forces,  to  cover  the  dry 
land  of  either  half  of  the  globe  with  a  beautiful 
abundance  of  individual  forms,  and  to  free  at 
least  the  greater  portion  of  it  from  the  blank 
of  uniformity  which  appears  to  cramp  and  im- 
poverish both  the  physical  and  the  intellectual 
powers  of  man. 

To  each  system(327)  of  these  mountain  chains 
there  is,  according  to  the  grand  views  of  Elie 
de  Beaumont,  a  relative  age  to  be  assigned  : 
the  upheaval  of  the  range  must  necessarily  fall 
between  the  times  when  the  erupted  strata 
were  deposited,  and  those  in  which  the  hori- 
zontal beds,  that  stretch  up  to  the  very  foot  of 
the  mountains,  were  laid  down.  The  furrow- 
ings  of  the  crust  of  the  earth,  in  other  words, 
the  erections  of  strata  which  are  of  like  geo- 
logical age,  appear,  moreover,  to  attach  them- 
selves to  one  and  the  same  direction.  The 
line  of  strike,  or  heaving  of  the  strata,  is  not 
always  parallel  to  the  axis  of  the  chain,  but 
sometimes  cuts  it  through  ;  so  that,  according 
to  my  views(32^),  the  phenomenon  of  erection 
of  strata  which  is  even  found  repeated  in  the 
neighbouring  level,  must  be  older  than  the  ele- 
vation of  the  chain.  The  principal  direction 
of  the  whole  of  the  dry-land  in  Europe  (south- 
west to  north-east)  is  opposed  to  the  great  fis- 
sure or  valley  which  runs  from  north-west  to 
south-east,  from  the  mouths  of  the  Rhine  and 
the  Elbe,  through  the  Adriatic  and  Red  Sea, 
across  the  mountain  system  of  Puschti-Koh  in 


PHYSICAL  GEOGRAPHY— THJ».  OCEAN. 


91 


Luristan,  towards  the  Persian  Gulf  and  the 
Indian  Ocean.  Such  a  nearly  rectangular  in- 
tersection of  geodetical  lines  has  exerted  a 
vast  influence  on  the  commercial  relations  of 
Europe  with  Asia  and  the  north-west  of  Africa, 
as  wejl  as  on  the  march  of  civilization  along 
the  once  more  fortunate  shores  of  the  Mediter- 
ranean Sea("»). 

If  vast  and  lofty  mountain  chains  appear  to 
our  imagination  as  evidences  of  great  revolu- 
tions undergone  by  the  surface  of  the  earth,  as 
boundaries  of  climates,  as  dividers  and  deter- 
miners of  the  courses  of  rivers,  as  bearers  of 
another  vegetable  world,  it  is  the  more  neces- 
sary, by  accurate  numerical  estimates  of  their 
volumes,  to  show  how  insignificant,  on  the 
whole,  is  the  quantity  of  the  upheaved  masses 
in  contrast  with  the  areas  of  entire  continents. 
The  mass  of  the  Pyrenees,  for  example,  a  chain 
the  mean  height  of  whose  ridges,  and  the  ex- 
tent of  surface  of  the  base  which  it  covers, 
have  been  ascertained  by  accurate  measure- 
ments, if  distributed  evenly  over  the  area  of 
France,  would  raise  the  surface  of  that  coun- 
try by  no  more  than  about  108  feet.  The  mass 
of  the  eastern  and  western  Alps,  spread  in  the 
same  way  over  the  area  of  Europe,  would  only 
raise  the  land  by  about  20  feet.  By  a  laborious 
calculation("0),  which  from  its  nature  can  only 
give  an  extreme  superior  limit,  in  other  words, 
a  number  which  may  be  less,  but  cannot  be 
greater  th^  the  truth,  I  have  found  that  the 
centre  of  gravity  of  the  volume  of  the  coun- 
tries which  in  Europe  and  North  America  rise 
above  the  level  of  the  sea,  lies  at  a  height  of 
630  and  702  feet,  and  in  Asia  and  South  Amer- 
ica, at  an  elevation  of  1062  and  1080  feet. 
These  estimates  show  the  slight  elevation  of 
the  northern  regions  :  the  vast  steppes  of  the 
Siberian  levels  are  compensated  by  the  enor- 
mous rise  of  the  Asiatic  soil  from  28p  to  40° 
N.  lat.  between  the  Himalaya,  the  north  Thi- 
betic  Kuen-luen,  and  the  Thianschan  or  Celes- 
tial Mountains.  We  read,  to  a  certain  extent, 
in  the  numbers  found,  where  the  Plutonic  forces 
of  the  interior  of  the  earth  have  put  forth  their 
greatest  strength  in  uplifting  continental  masses. 

There  is  nothing  to  assure  us  that  these  Plu- 
tonic powers  may  not  in  the  course  of  future 
centuries  add  new  members  to  the  mountain 
systems  of  different  ages  and  having  different 
directions,  which  have  been  enumerated  by  Elie 
de  Beaumont.  Wherefore  should  the  crust  of 
the  earth  have  lost  the  property  of  folding  on 
itself  1  Almost  the  last  of  the  mountain  sys- 
tems that  appeared,  the  Alps  and  the  Andes, 
have  reared  colossuses  in  Mont-Blanc  and 
Monte  Rosa,  in  Sorata,  lUimani  and  Chimbo- 
razo,  that  do  not  allow  us  to  infer  any  falling 
off  in  the  intensity  of  the  subterranean  forces. 
Geological  phenomena  of  all  kinds  indicate  al- 
ternating periods  of  activity  and  r^se("i). 
The  repose  we  now  enjoy  is  only  apparent. 
The  shocks  which  the  surface  experiences  un- 
der every  variety  of  climate,  and  along  with 
every  description  of  rock,  Sweden  rising  in  its 
level,  and  the  appearance  of  new  eruptive  isl- 
ands, bear  no  testimony  to  quiescence  in  the 
internal  life  of  the  globe. 

The  two  coverings  of  the  solid  crust  of  our 
planet — the  liquid  and  the  gaseous,  the  ocean 
and  the   atmosphere,  besides  the   contrasts 


which  arise  from  the  great  diversities  in  theii 
states  of  aggregation  and  elasticity — also  pre- 
sent numerous  analogies  by  reason  of  the  mo- 
bility of  their  particles,  of  their  currents,  and 
their  relations  to  temperature.  The  depth  of 
the  sea  and  of  the  aerial  ocean  are  both  of  thera 
unknown  to  us.  In  some  places  under  thf 
tropics  no  bottom  has  been  found  to  the  sea 
with  25,300  feet  of  line  (more  than  a  [German] 
geographical  mile) ;  and  the  atmosphere,  sup- 
posing it,  as  Wollaston  will  have  it,  to  be  lim- 
ited and  so  subject  to  undulations,  may  be  in- 
ferred, from  the  phenomena  of  twilight,  to  have 
a  nine-times  greater  profundity.  The  aerial 
ocean  rests  partly  on  the  solid  earth,  whose 
mountain  chains  and  lofty  table-lands,  as  al- 
ready said,  rise  up  like  green  and  wood-crown- 
ed shoals  ;  partly  on  the  ocean,  whose  surface 
forms  the  fluctuating  bottom  upon  which  the 
inferior  denser  and  moister  strata  repose. 

From  the  limits  of  both  the  atmosphere  and 
the  ocean  upwards  and  downwards,  the  aerial 
and  liquid  strata  are  alike  subjected  to  certain 
laws  of  decrease  of  temperature.  In  the  at- 
mosphere this  decrease  is  much  slower  than  in 
the  ocean.  Under  every  zone  the  tendency  of 
the  sea  is  to  preserve  the  temperature  of  its 
surface  in  equilibrium  with  that  of  the  stratum 
of  air  which  rests  immediately  upon  it,  inas- 
much as  the  chilled  particles  [supposing  the 
temperature  of  the  air  to  be  the  lower]  sink, 
[and  the  warmer  particles,  vice  versa,  keep  their 
place  on  the  surface].  A  vast  series  of  care- 
ful observations  on  temperature,  teach  us  that 
in  the  usual  and  mean  state  of  its  surface,  the 
ocean,  from  the  equator  to  58°  of  north  and 
south  latitude,  is  somewhat  warmer  than  the 
stratum  of  air  that  rests  immediately  upon 
it("2).  On  account  of  the  decrement  of  tem- 
perature with  the  increasing  depth,  fishes  and 
the  other  inhabitants  of  the  sea,  which,  by  rea- 
son perhaps  of  the  nature  of  their  branchial  and 
cutaneous  respiratory  systems,  love  deep  wa- 
ter, are  able  to  find  the  lower  temperatures, 
that  agree  particularly  with  them  in  higher  lat- 
itudes, under  the  temperate  and  colder  zones. 
This  circumstance,  analogous  to  the  temperate, 
even  to  the  cold  alpine  atmospheres  of  the  lofty 
plateaus  of  the  torrid  zone,  exerts  an  essential 
influence  on  the  migrations  and  geographical 
distribution  of  many  marine  animals.  The 
depths  in  which  fishes  live,  by  the  increase  of 
pressure  they  occasion,  modify  in  like  measure 
the  cutaneous  respiration  and  the  contents  in 
oxygen  and  azote  of  the  air  in  the  swimming 
bladder. 

As  fresh  and  salt  water  do  not  attain  their 
maximum  density  at  the  same  temperature, 
and  the  saline  contents  of  the  sea  cause  the 
thermometrical  indication  of  greatest  density 
to  descend,  water  was  obtained  from  the  abyss 
of  the  ocean  in  the  voyages  of  Kotzebue  and 
Dupetit-Thouars,  which  indicated  the  low  de- 
grees of  2  8°  and  25°  C.  This  icy  temperature 
of  the  water  also  prevails  in  the  depths  of  the 
tropical  sea,  and  its  discovery  gave  the  first  in- 
formation of  the  existence  of  inferior  polar  cur- 
rents, proceeding  from  either  pole  towards  the 
equator.  Without  such  under-sea  currents,  the 
abyss  of  the  tropical  ocean  could  only  have  a 
temperature  equal  to  the  maximum  of  cold 
which  the  particles  of  water  descending  locallj 


93 


PHYSICAL  GEOGRAPHY— THE  OCEAN. 


from  the  surface  radiating  heat,  and  cooled  by 
the  contact  of  the  atmosphere,  could  acquire  in 
a  tropical  region.  In  the  Mediterranean  Sea, 
as  Arago  acutely  observes,  a  corresponding 
great  depression  of  temperature  in  the  inferior 
strata  is  only  not  observed,  because  the  influx 
of  the  deep  polar  stream  by  the  Straits  of  Gib- 
raltar, through  which  the  Atlantic  is  flowing 
from  west  to  east,  is  encountered  by  a  west- 
ward under-current  of  the  Mediterranean  to- 
wards the  Atlantic. 

The  fluid-covering  of  our  planet,  equalizing 
and  tempering  climates  in  general,  where  it  is 
not  intersected  by  pelagic  currents  of  colder  or 
warmer  water,  and  far  from  the  coasts  of  trop- 
ical countries,  particularly  between  10°  north 
and  10°  south  latitude,  may  be  said  to  exhibit 
a  truly  wonderful  equality  and  steadiness  of 
temperature  over  areas  that  are  thousands  of 
square  miles  in  extent(333).  It  has,  therefore, 
been  said  with  reason(^^*),  that  a  long- contin- 
ued and  careful  investigation  of  the  thermal 
relations  of  the  tropical  seas  would  give  us  in- 
formation in  the  simplest  manner  on  the  grand 
and  much  discussed  problem  of  the  constancy 
of  climates,  and  of  the  temperature  of  the  earth. 
Great  revolutions  in  the  luminous  disc  of  the 
sun,  were  they  of  long  continuance,  would  be 
simultaneously  reflected  in  the  altered  mean 
temperature  of  the  sea  still  more  certainly  than 
in  the  mean  temperature  of  the  land. 

The  zones  in  which  the  maxima  of  density 
(saline  contents)  and  temperature  lie,  do  not 
coincide  with  the  equator.  The  two  maxima 
are  distinct  from  one  another,  and  the  warmest 
water  appears  to  form  two  not  completely  par- 
allel bauds  to  the  north  and  south  of  the  geo- 
graphical equator.  The  maximum  of  saline 
contents  was  found  by  Lenz,  in  his  voyage 
round  the  world,  in  the  Pacific,  in  the  two  par- 
allels of  22°  north  and  17°  south  latitude.  The 
zone  of  least  density,  again,  was  found  to  lie 
a  few  degrees  to  the  south  of  the  line.  In  the 
region  of  the  Calms,  the  heat  of  the  sun  can- 
not occasion  any  great  amount  of  evaporation, 
because  a  stratum  of  air  saturated  with  saline 
vapour  there  sleeps  unmoved  and  unrenewed 
upon  the  surface  of  the  ocean. 

The  surface  of  all  the  seas  that  communi- 
cate one  with  another,  must  be  regarded  as 
generally  perfectly  equal  in  respect  of  mean 
elevation.  Local  causes,  mostly  prevailing 
winds  and  currents,  have,  however,  in  particu- 
lar extensively  land-locked  seas — the  Red  Sea, 
for  example,  produced  permanent,  though  still 
inconsiderable  differences  of  level.  At  the  isth- 
mus of  Suez  the  level  of  the  Red  Sea  is  from  24 
to  36  feet  above  that  of  the  Mediterranean  at 
diflferent  hours  of  the  day.  The  form  of  the  ca- 
nal, (the  Straits  of  Babelmandel),  by  which  the 
Indian  Ocean  communicates  with  the  Red  Sea, 
being  such,  that  the  waters  find  a  readier  ac- 
cess than  outlet,  appears  to  assist  in  producing 
this  remarkable  permanent  superior  elevation 
of  the  surface  of  the  Red  Sea,  which  was  al- 
ready known  to  the  Ancients(^3^).  The  admi- 
rable geodetical  operations  of  Coraboeuf  and 
Delcros  along  the  chain  of  the  Pyrenees,  have 
shown  that  there  is  no  appreciable  difference 
in  the  surface  of  equilibrium,  in  the  sea-level, 
on  the  north  coast  of  Holland  and  at  Marseilles, 
of  the  ocean  and  the  Mediterranean("^). 


Disturbances  of  the  Equilibrium  and  motions 
of  the  mass  of  waters  consequent  on  these, 
sometimes  irregular  and  transient,  depending 
on  winds  and  producing  Waves  which  in  the 
open  ocean  and  far  from  land  mount  during  a 
storm  to  a  height  of  35  feet  and  more  ;  in  oth- 
er instances,  regular  and  periodical,  occasioned 
by  the  position  and  attraction  of  the  sun  and 
moon — the  Tides  ;  in  still  other  instances,  per- 
manent, but  of  unequal  force,  as  Oceanic  cur- 
rents. The  phenomena  of  ebb  and  flow,  which 
extend  over  every  sea  with  the  exception  of 
those  that  are  very  small  and  much  land-locked, 
in  which  the  tidal  wave  is  either  little  or  not 
at  all  observable,  are  completely  explained  by 
the  Newtonian  natural  philosophy,  i.  e.  referred 
to  the  circle  of  necessary  effects.  Each  of 
these  periodically  recurring  oscillations  of  the 
ocean,  is  somewhat  longer  than  half  a  day.  In 
the  open  ocean  they  scarcely  rise  to  the  extent 
of  a  few  feet ;  but  in  consequence  of  the  posi- 
tion and  configuration  of  coasts  and  estuaries 
which  meet  the  coming  tidal  wave  they  rise  in 
some  places  to  extraordinary  heights — in  St. 
Malo  to  50  feet,  and  in  Acadia,  Nova-Scotia, 
to  from  65  to  70  feet.  "  Under  the  supposition 
that  the  depth  of  the  ocean  is  inconsiderable 
when  contrasted  with  the  semi-diameter  of  the 
earth,  the  analysis  of  the  great  geometrician 
Laplace,  has  shown  how  the  stability  in  the 
equilibrium  of  the  ocean  requires  that  the  dens- 
ity of  its  fluid  should  be  less  than  the  mean 
density  of  the  earth."  And  indeed,%s  we  have 
seen  above,  the  density  of  the  oarth  is  five- 
times  greater  than  that  of  water.  The  high 
lands  of  the  earth,  therefore,  can  never  be  over- 
flowed, and  the  remains  of  marine  animals 
found  on  mountains  can  by  no  means  have  been 
brought  into  such  situations  by  former  floods 
or  deluges  produced  by  the  position  of  the  sun 
and  moon(33^).  j|;  jg  ^q  trifling  tribute  to  analy- 
sis, which  in  the  unscientific  circles  of  society 
is  presumptuously  held  so  cheap,  that  Laplace's 
perfected  Theory  of  the  Tides  has  made  it  pos- 
sible to  predict  in  our  astronomical  ephemerides 
or  nautical  almanacks,  the  height  of  the  spring- 
tide to  be  expected  at  each  new  and  full  moon, 
and  so  to  forewarn  the  inhabitants  of  the  coasts 
of  the  increased  danger  with  which  they  are 
threatened  at  these  seasons,  particularly  when 
the  moon  is  in  her  perigee. 

Oceanic  currents,  which  exercise  so  consid- 
erable an  influence  on  the  intercourse  of  na- 
tions and  on  the  climatic  relations  of  coasts, 
are  almost  simultaneously  dependent  on  a  mul- 
titude of  very  dissimilar,  now  greater,  now  ap- 
parently more  insignificant  causes.  To  the 
number  of  these  belong  :  the  progressive  time 
of  appearance  of  the  ebb  and  flow  of  the  tidal 
wave  in  its  course  round  the  vi'orld ;  the  dura- 
tion and  force  of  prevailing  winds  ;  the  density 
and  spagific  gravity  of  the  watery  particles 
modified  under  different  parallels  of  latitude  by 
their  temperature  and  saline  impregnations('^*) ; 
the  horary  variations  of  the  atmospheric  press- 
ure, which  proceed  successively  from  east  to 
west  with  such  regularity  within  the  tropics. 
The  currents  of  the  ocean  present  this  remark- 
able spectacle  :  that  they  cross  it  of  definite 
breadths  in  different  directions,  in  the  manner 
of  rivers,  neighbouring  unmoved  watery  strata, 
forming  the  banks,  as  it  were,  of  these  streams. 


PHYSICAL  GEOGRAPHY— THE  OCEAN. 


93 


This  distinction  between  the  portion  which  is 
moved  and  that  which  is  at  rest,  is  most  re- 
markable where  large  quantities  of  sea-weed 
carried  along  with  the  current  permit  us  to  esti- 
mate its  velocity.  We  occasionally  observe 
similar  phenomena  of  limited  currents  in  the 
inferior  strata  of  the  atmosphere  :  after  tem- 
pests that  have  swept  over  dense  forests,  it 
sometimes  happens  that  the  trees  are  only  found 
shattered  and  blown  down  in  the  course  of  nar- 
row strips. 

The  general  motion  of  the  sea  between  the 
tropics  from  east  to  west,  entitled  the  equato- 
rial current,  is  regarded  as  a  consequence  of 
the  advancing  times  of  the  tides  and  of  the 
trade  winds.  It  alters  its  direction  in  conse- 
quence of  the  resistance  of  the  east  coasts  of 
the  continents  which  it  encounters  in  its  prog- 
ress. The  new  results  w^hich  Daussy  has  ob- 
tained from  the  motion  of  bottles  thrown  out 
on  purpose  by  navigators  (10  French  sea  miles, 
of  925  toises  each,  every  24  hours),  argees  to 
within  Jgth  of  the  velocity  which  I  had  ascer- 
tained from  a  comparison  of  earlier  data("'). 
In  the  log-book  of  his  third  voyage  (the  first  in 
which  he  sought  to  make  the  tropics  in  the  me- 
ridian of  the  Canaries),  Christopher  Columbus 
says  :  "  I  hold  it  as  certain  that  the  waters  of 
the  sea  move  with  the  heavens  {las  aguas  van 
con  los  cielos),^^  that  is  to  say,  from  east  to  west, 
like  the  apparent  motion  of  the  sun,  moon,  and 
stars(3*o). 

The  narrow  currents,  true  oceanic  rivers, 
which  take  their  way  through  the  sea,  run 
warmer  water  in  higher,  colder  water  in  lower 
latitudes.  To  the  first  class  belongs  the  cele- 
brated Gulf-stream("'),  which  was  known  to 
Anghiera(3<2),  and  particularly  to  Sir  Humfrey 
Gilbert  in  the  16th  century.  The  commence- 
ment and  first  impulse  of  this  mighty  current 
is  to  be  sought  for  southAvard  from  the  Cape 
of  Good  Hope,  and  it  debouches  from  the  Ca- 
ribbean Sea  and  the  Gulf  of  Mexico,  through 
the  Straits  of  Bahama  ;  running  from  south- 
south-west  to  north-north-east,  getting  farther 
and  farther  from  the  shores  of  the  United  States 
of  America,  it  turns  off  eastward  by  the  banks 
of  Newfoundland,  crosses  the  Atlantic,  and 
frequently  throws  the  seeds  of  tropical  plants 
(Mimosa  scandens,  Guilandina  bonduc,  Doli- 
chos  urens),  upon  the  coasts  of  Ireland,  the 
Hebrides  and  Norway.  The  north-eastern 
prolongation  of  the  Gulf-stream  contributes  to 
moderate  the  cold  of  the  sea-water  and  also  of 
the  climate  about  the  north  Cape  of  Scandina- 
via. The  warm  Gulf-stream,  after  it  has  turn- 
ed eastward  from  the  banks  of  Newfoundland, 
at  no  great  distance  from  the  Azores,  sends 
off  a  branch  to  the  south,  and  it  is  here  that 
the  Sargasso-sea,  as  it  has  been  called,  the 
great  bank  of  sea-weed,  is  met  with,  which 
made  so  lively  an  impression  on  the  imagina- 
tion of  Columbus,  and  which  Oviedo  called  the 
sea-weed  meadow  (Praderias  de  Yerva).  A 
host  of  small  marine  animals  inhabit  this  ever- 
verdant  mass  of  Fucus  natans,  one  of  the  most 
widely  diffused  of  the  social  plants  of  the 
ocean,  which  is  constantly  drifted  hither  and 
thither  by  the  tepid  winds  that  blow  across  its 
surface. 

In  contrast  to  the  Gulf-stream,  which  belongs 
almost  exclusively  to  the  northern  hemisphere 


I  of  the  Atlantic  valley,  and  runs  between  Amer-  ^ 
'  ica,  and  Europe  and.  Africa,  is  the  great  cur- 
rent of  the  Pacific  Ocean,  the  inferior  tempera- 
ture of  whose  waters  has  an  appreciable  influ- 
ence on  the  climate  of  the  sea-boards  along 
which  it  sweeps,  as  I  first  observed  in  the  au- 
tumn of  1802(3*3).  This  currenr,  in  fact,  brings 
the  dolder  water  of  high  southern  latitudes  to 
the  coast  of  Chili,  runs  along  the  shores  of  this 
country  and  those  of  Peru,  first  from  south  to 
north,  and  then  (from  the  bay  of  Arica)  from 
south-south-east  to  north-north-west.  In  the 
middle  of  the  tropics  at  certain  seasons  of  the 
year  the  water  of  this  cold  ocean  stream  is  not 
higher  than  15°  6  C.  (60°  0  F.),  whilst  the  motion- 
less water  beyond  its  limits  is  as  high  as  from 
27°  5  to  28°  7  C.  (81°  5  to  84°  6  F.).  Where 
the  sea-board  of  South  America,  southward 
from  Payta,  advances  farthest  to  the  west,  the 
stream  turns  suddenly  in  the  same  direction 
from  off  the  land,  and  takes  a  course  from  east 
to  west ;  so  that  he  who  sails  northward  [by 
crossing  the  stream]  comes  suddenly  from  a 
colder  to  a  warmer  sea. 

It  is  not  known  to  what  depth  the  oceanic 
currents,  whether  hot  or  cold,  extend,  how 
near  they  run  to  the  bottom.  The  deviation  of 
the  South  African  current  produced  by  the  La- 
gullas  bank,  where  the  water  is  full  70  or  80 
fathoitis  deep,  appears  to  indicate  a  considera- 
ble extension  in  depth.  Sand-banks  and  shoals 
outside  the  streams  are  mostly  recogniza- 
ble, as  the  excellent  Benjamin  Franklin  dis- 
covered, by  the  coldness  of  the  water  over 
them.  This  depression  of  temperature  appears 
to  me  to  be  connected  with  the  circumstance, 
that  with  the  communication  of  motion  to  the 
neighbouring  ocean,  deep  cold  water  is  made 
to  rise  over  the  edges  of  the  banks  and  to  mix 
with  the  upper  warmer  water.  My  immortal 
friend.  Sir  Humphrey  Davy,  on  the  other  hand, 
ascribed  the  phenomenon,  from  which  the  sea- 
man can  frequently  draw  practical  inferences 
conducive  to  his  safety,  to  the  descent  of  the 
superficial  strata  of  water  cooled  in  the  course 
of  the  night :  these  remain  nearer  the  surface, 
because  the  shoal  prevents  them  from  sinking 
to  a  greater  depth.  The  thermometer  was 
turned  by  Franklin  into  a  plumb-hne  ;  fogs  are 
frequent  upon  banks  and  shoals :  their  colder 
water  causes  precipitation  of  the  vapour  that 
is  dissolved  in  the  sea  air.  I  have  observed 
such  fogs  to  the  south  of  Jamaica,  and  also  in 
the  Pacific,  indicating  the  outline  of  shoals 
sharply  and  quite  distinctly  from  a  distance. 
They  present  themselves  to  the  eye  like  air- 
pictures,  in  which  the  fashion  of  the  sub-mari- 
time bottom  is  reflected.  A  still  more  remark- 
able influence  of  these  cold  shallows  is  this, 
that  they  produce  an  obvious  effect  upon  the 
superior  strata  of  the  atmosphere,  almost  in  the 
same  way  as  low  coral  or  sandy  islands.  Far 
from  all  land,  in  the  high  seas,  when  the  air  is 
elsewhere  quite  clear,  clouds  are  frequently 
seen  hovering  over  the  spots  where  shoals  oc- 
cur. In  such  cases  their  jjearings  can  be  taken 
by  the  compass,  precisely  as  if  they  were  lofty 
mountains  or  isolated  peaks. 

Without  the  variety  of  external  forms  that 
characterize  the  surface  of  continents,  the 
ocean,  when  its  interior  is  narrowly  scanned. 


94 


THE   ATMOSPHERE. 


^  presents  a  greater  mass  of  organic  life  than  is 
perhaps  to  be  found  collected  together  in  any 
other  portion  of  the  earth's  surface.  Charles 
Darwin  observes  with  justice,  in  the  interest- 
ing Journal  of  his  extensive  sea-voyage,  that 
our  woods  on  shore  do  not  harbour  so  many 
animals  as  the  woody  regions  of  the  ocean, 
where  the  sea-weed  groves,  rooted  to  the  bot- 
tom of  the  shallows,  or  the  fuci  detached  by 
waves  and  currents,  supported  by  air-cells  and 
swimming  free,  unfold  their  delicate  arms  and 
branches.  The  use  of  the  microscope  increases 
still  farther,  and  in  the  most  remarkable  man- 
ner, the  impression  of  the  universal  life  of  the 
ocean,  the  astounding  assurance  that  here  sen- 
sibility is  everywhere  diffused  and  active.  In 
depths  that  surpass  the  height  of  our  most  lofty 
mountains,  every  one  of  the  several  superposed 
strata  of  waters,  is  animated  with  its  own  Poly- 
gastric  worms,  Cyclidia,  and  Ophrydia.  Here 
swarm,  turning  each  wave  into  luminous  foam, 
and  attracted  to  the  surface  by  particular  weath- 
er-influences, the  innumerable  host  of  small 
light-flashing  Mammaria  from  the  Orders  of  the 
Acalephee,  Crustacea,  Peridinia,  and  Nereides 
moving  in  circles. 

The  abundance  of  these  small  animals,  and 
of  the  animal  matter  which  their  rapid  destruc- 
tion supplies,  is  so  immeasurable,  that  the  sea- 
water  at  large  becomes  a  nutritious  fltiid  for 
much  larger  creatures.  If  this  exuberance  of 
living  forms,  these  myriads  of  dissimilar  nAi- 
croscopical,  and  yet  in  ^art  extremely  perfect 
organisms,  engage  and  pleasantly  excite  the 
fancy,  this  is  appealed  to  in  a  more  earnest,  I 
might  say  a  more  solemn  manner,  by  the  sense 
of  the  Limitless  and  the  Immeasurable,  w^hich 
every  sea-voyage  presents  to  our  contempla- 
tion. He  who  is  awakened  to  a  spiritual  self- 
activity,  and  who  delights  to  build  up  a  world 
within  himself,  fills  the  amphitheatre  of  the 
boundless  ocean  with  the  lofty  image  of  the 
Infinite  and  the  Endless.  His  eye  is  fixed 
especially  by  the  far  horizon,  where  indefinite- 
ly and  as  in  mist,  the  ocean  and  the  air  meet 
bounding  one  another,  in  which  the  stars  set  and 
rise  anew  before  the  eyes  of  the  beholder.  .But 
still,  with  the  eternal  play  of  this  interchanging 
scene,  as  everywhere  else  with  human  happi- 
ness, there  comes  the  breath  of  sadness,  of  un- 
gratified  longing,  to  mix  itself  with  the  joy. 

A  peculiar  predilection  for  the  sea,  grateful 
remembrances  of  the  impressions  which  the 
mobile  element  between  the  tropics,  in  the 
peace  and  silence  of  the  night,  or  roused  and 
at  war  with  the  natural  forces,  has  left  upon 
my  mind,  could  alone  have  induced  me  to  speak 
of  the  individual  enjoyment  of  the  prospect,  be- 
fore referring  to  the  beneficial  influence  which 
contact  with  the  ocean  has  had  on  the  devel- 
opment of  the  intelligence  and  character  of  va- 
rious nations ;  on  the  multiplication  by  its 
means  of  the  bonds  that  ought  to  embrace  the 
whole  of  the  human  family  ;  on  the  possibility 
it  has  aflx)rded  of  attaining  to  a  knowledge  of 
the-  configuration  qf  the  earth  and  its  parts ; 
lastly,  on  the  improvement  it  has  led  to  in  as- 
tronomy, and  in  the  mathematical  and  natural 
sciences  at  large.  A  portion  of  this  influence 
was  originally  confined  to  the  waters  and  the 
shores  of  the  south-western  parts  of  Asia ;  but 
from  the  16th  century  onwards  it  has  extended 


far  and  wide,  and  even  attained  to  nations  that 
live  in  the  interior  of  continents  remote  from 
the  sea.  Since  Christopher  Columbus  was 
"  sent  forth  to  unchain  the  ocean'X^'**)  (for  so 
was  he  addressed  in  a  dream  by  an  unknown 
voice  whilst  he  lay  on  a  sick-bed  by  the  river 
Belem),  man,  too,  mentally  more  free,  has  ven- 
tured with  greater  boldness  into  unknown  re- 
gions. 

The  second  and  most  external  and  univer- 
sally diffused  of  the  coverings  of  our  globe,  the 
Atmosphere,  on  whose  depths,  or  shoals,  which 
are  lofty  table-lands  and  mountains,  we  live, 
present  six  classes  of  natural  phenomena,  con- 
nected in  the  most  intimate  manner  with  one 
another  ;  these  are  :  chemical  composition  ; 
alterations  in  the  transparency,  polarization, 
and  colour  ;  in  the  density  or  pressure  ;  in  the 
temperature,  humidity,  and  electricity.  If  in 
its  oxygen  the  air  contains  the  first  element  of 
physical  animal  life,  another  excellence,  it 
might  almost  be  said  of  a  higher  order,  must  be 
indicated  in  its  constitution.  The  air  is  the 
"  carrier  of  sound,"  and  so  also  the  bearer  of 
speech,  the  means  of  communicating  ideas,  of 
maintaining  social  intercourse  among  men.  The 
earth,  robbed  of  its  atmosphere,  like  the  moon, 
presents  itself  to  the  imagination  as  a  desert 
brooded  over  by  silence. 

The  relations  of  the  substances  which  be- 
long to  the  strata  of  the  atmosphere  that  are 
accessible  to  us,  have,  since  the  beginning  of 
the  19th  century,  been  made  the  object  of  re- 
searches, in  which  Gay  Lussac  and  I  took  an 
active  part ;  it  is  but  very  recently,  however, 
through  the  admirable  labours  of  Dumas  and 
Boussingault,  that  the  chemical  analysis  of  the 
atmosphere,  pursued  in  new  and  trustworthy 
ways,  has  been  advanced  to  a  high  degree  of 
perfection.  From  this  analysis  dry  air  appears 
to  contain  per  volume  28-8  oxygen,  and  792 
azote  ;  besides  from  2  to  5  ten  thousands  of 
carbonic  acid,  a  still  smaller  quantity  of  carbu- 
retted  hydrogen(3*5),  and  from  the  important 
experiments  of  Saussure  and  Liebig,  traces  of 
ammoniacal  vapours(^"),  which  may  supply 
plants  with  their  azotized  constituents.  That 
the  quantity  of  oxygen  may  vary  in  a  trifling 
but  still  appreciable  degree  according  to  season, 
situation  of  a  place — upon  the  sea  or  in  the  in- 
terior of  a  continent — has  been  rendered  prob- 
able by  some  observations  of  Lewy.  It  is  con- 
ceivable that  changes  in  the  quantity  of  oxygen 
held  in  solution  by  water,  induced  by  micro- 
scopical animal  organisms,  may  be  followed  by 
changes  in  the  strata  of  air  that  lie  in  immedi- 
ate contact  with  its  surface(^*^).  The  air  col- 
lected by  Martins  on  the  Faulhorn  at  a  height 
of  8226  feet,  did  not  contain  more  oxygen  than 
the  air  of  Paris(3*8). 

The  admixture  of  carbonate  of  ammonia  in 
the  atmosphere  may  probably  be  held  as  older 
than  the  existence  of  organic  beings  on  the  sur- 
face of  the  earth.  The  sources  of  the  carbon- 
ic acid  of  the  atmosphere  are  extremely  nu- 
merous(^*').  We  may  here  mention  the  res- 
piration of  animals,  which  receive  the  carbon 
they  exhale  from  the  vegetable  food  they  con- 
sume, as  vegetables  themselves  derive  it  from 
the  atmosphere ;  the  interior  of  the  earth  in 
the  country  of  extinct  volcanoes  and  thermal 


THE  ATMOSPHERE— PRESSURE. 


95 


springs ;  the  decomposition  of  the  slight  ad- 
mixture of  carburetted  hydrogen  contained  in 
the  atmosphere,  by  the  electrical  discharges  of 
the  clouds,  so  frequent  in  intertropical  coun- 
tries. 

Besides  the  substances  which  have  just  been 
mentioned,  and  which  may  be  held  proper  to 
the  atmosphere  under  all  circumstances  and  in 
all  situations,  there  are  other  accidental  mat- 
ters associated  with  it,  which  occur  especially 
near  the  ground,  and  of  which  several,  desig- 
nated miasms  and  contagions,  affect  the  animal 
system  prejudicially.  The  chemical  nature  of 
these  substances  has  not  yet  been  made  known 
by  any  immediate  analysis  ;  but,  considering  the 
putrefactive  processes  which  proceed  inces- 
santly on  the  surface  of  our  planet,  covered  as 
it  is  with  animal  and  vegetable  matters,  and  led 
as  well  by  combinations  and  analogies  derived 
from  the  domain  of  pathology,  we  may  fairly 
conclude  on  the  existence  of  such  injurious  lo- 
cal admixtures.  Ammoniacal  and  other  azo- 
tized  vapours,  sulphuretted  hydrogen,  combi- 
nations, indeed,  resembUng  the  multibasic,  (ter- 
nary and  quarternary),  compounds  of  the  vege- 
table kingdom("°),  may  form  miasmata,  which, 
in  a  variety  of  shapes,  and  by  no  means  only 
on  naked  swampy  bottoms,  or  on  sea-coasts 
strewed  with  putrifying  molluscs,  or  covered 
with  under-growths  of  mangrove  (Rhizophora), 
and  Avicenniae,  may  produce  fevers  of  aguish 
or  typhoid  types.  Fogs  which  diffuse  a  pecu- 
liar smell,  remind  us  at  certain  seasons  of  the 
year  of  such  accidental  contaminations  of  the 
lower  strata  of  the  atmosphere.  Winds  and 
ascending  currents  of  air  occasioned  by  tlie 
heating  of  the  surface,  raise  even  solid,  though 
of  course  finely  pulverized  substances,  to  con- 
siderable heights.  The  dust,  which  makes  the 
air  misty  over  a  great  area,  and  falls  about  the 
Cape  de  Verd  Islands,  to  which  Darwin  has  so 
properly  directed  attention,  is  found  from  Eh- 
renberg's  observations  to  contain  an  infinity  of 
silicious  shelled  infusory  animalcules. 

As  principal  features  in  a  general  physical 
picture  of  the  atmosphere,  we  may  distinguish, 
1st.  In  the  variations  of  the  air's  pressure  :  the 
regular,  and  between  the  tropics,  so  readily  ap- 
preciable hourly  oscillations,  a  kind  of  ebb  and 
flow  of  the  atmosphere,  which  cannot  be  as- 
cribed to  the  attraction  of  the  mass  of  the 
moon("^),  and  which  is  so  different  according 
to  the  latitude,  the  season  of  the  year,  and  the 
height  of  the  place  of  observation  above  the 
level  of  the  sea.  2d.  In  the  climatic  distribu- 
tion of  heat :  the  influence  of  the  relative  posi- 
tion of  the  transparent  and  opaque  masses — 
the  fluid  and  solid  superficial  areas,  as  well  as 
of  the  hypsometrical  or  perpendicular  configu- 
ration of  continents,  relations  which  determine 
the  geographical  position  and  curvature  of  the 
isothermal  lines*  in  the  horizontal  or  vertical 
direction,  in  the  ground-plane,  or  in  the  aerial 
strata  lying  one  above  another.  3d.  In  the  dis- 
tribution of  the  moisture  of  the  atmosphere : 
the  consideration  of  the  quantitative  relations 
according  to  diversity  in  the  solid  and  oceanic 
surfaces,  distance  from  the  equator,  and  height 
above  the  level  of  the  sea ;  the  forms  in  which 
precipitation  of  the  watery  vapour  takes  place, 


*  Lines  of  equal  mean  temperature. 


and  the  connection  of  this  precipitation  with 
the  changes  of  temperature,  and  the  direction 
as  well  as  the  succession  of  the  winds.  4th. 
In  the  relations  of  the  aerial  electricity,  whose 
primary  source,  when  the  air  is  serene,  is  still 
much  disputed  :  the  relation  of  ascending  va- 
pours to  the  electrical  charge  and  the  fashion 
of  clouds  according  to  the  time  of  the  day  and 
the  season  of  the  year,  the  colder  or  hotter 
zones  of  the  earth,  the  lower  or  higher-lying 
plains  ;  the  frequency  and  rarity  of  storms ; 
their  periodicity  and  occurrence  in  summer  and 
winter;  the  casual  connection  of  electricity 
with  the  extremely  rare  occurrence  of  hail- 
showers  by  night,  as  also  with  water-spouts 
and  sand-spouts,  which  have  been  so  ably  in- 
vestigated by  Peltier. 

The  horary  variations  of  the  barometer,  in 
which  within  the  tropics  the  instrument  is  twice 
in  the  course  of  the  day  at  its  highest,  viz.,  at 
9  or  94  A.  M.  and  10  or  10|  p.  m.,  and  twice  at  its 
lowest,  viz.,  at  4  or  ^  p.  m.,  and  4  a.  m.,  nearly 
the  hottest  and  coldest  hours  in  the  round  of 
the  twenty-four,  consequently,  long  formed  the 
subject  of  my  most  careful  daily  and  nightly  ob- 
servations(3^2).  The  regularity  of  these  is  so 
great,  that  the  time,  especially  in  the  day,  may 
be  ascertained  by  the  height  of  the  column  of 
mercury,  without  an  error  on  the  average  of 
more  than  from  fifteen  to  seventeen  minutes. 
In  the  torrid  zone  of  the  New  Continent,  on  the 
coasts  as  well  as  on  heights  of  more  than  12,000 
feet  above  the  level  of  the  sea,  where  the  mean 
temperature  falls  to  7=  C  (43°  8  F.),  I  have  not 
found  the  regularity  of  this  ebb  and  flow  of  the 
atmosphere  to  be  disturbed  either  by  tempests 
of  thunder  or  of  wind,  by  rain  or  by  earthquakes. 
The  amount  of  the  daily  fluctuation  diminishes 
from  the  equator  on  to  70°  N.  latitude  (a  par- 
allel under  which  we  possess  very  accurate  ob- 
servations made  by  Bravais  at  Bosekop)  (3"), 
from  1-32  line,  to  0  18  line.  That,  much  near- 
er the  pole,  the  mean  height  of  the  barometer 
is  actually  less  at  10  a.  m.  than  at  4  p.  m.,  so 
that  the  times  of  the  maxima  and  minima  are 
severally  interchanged,  is  by  no  means  to  be 
concluded  from  Parry's  observations  at  Bowen 
Harbour  (73°  14'  N.  latitude). 

The  mean  height  of  the  barometer,  by  reason 
of  the  ascending  current  of  air,  is  somewhat 
less  under  the  equator,  and  especially  under  the 
tropics,  than  in  the  temperate  zone{^^*) ;  it  ap- 
pears to  attain  its  maximum,  in  the  West  of 
Europe,  in  the  parallels  of  40°  and  45°.  If, 
with  Kaemtz,  we  connect  those  places  which 
present  the  same  mean  differences  in  their 
monthly  barometrical  extremes  by  isobaromet- 
rical  lines,  curves  are  engendered,  the  geograph- 
ical position  and  direction  of  which  yield  us  im- 
portant conclusions  in  regard  to  the  influence  of 
the  configuration  of  continents,  and  the  expanse 
of  seas  upon  the  oscillations  of  the  atmosphere. 
Hindostan,  with  its  lofty  mountain  ranges  and 
triangular-shaped  peninsula,  the  East  coasts  of 
the  New  Continent,  at  the  point  where  the 
warm  gulf-stream  turns  eastward  by  New- 
foundland, show  greater  isobarometrical  fluctu- 
ations than  the  West  India  Islands,  and  the 
Western  parts  of  Europe.  Prevailing  winds 
exert  the  most  especial  influence  on  the  dimi- 
nution of  the  atmospheric  pressure,  and  with 
this,  according  to  Daussy,  as  we  have  already 


96 


THE  ATMOSPHERE— CLIMATE. 


observed,  the  mean  height  of  the  sea  is  increas- 
ed(3"). 

As  the  whole  of  the  most  important  varia- 
tions in  the  weight  or  pressure  of  the  atmo- 
sphere— whether  they  occur  regularly  at  certain 
hours  and  seasons,  or  are  accidental  and  ex- 
cessive, when  they  are  often  accompanied  with 
danger(^**) — like  all  the  rest  of  what  are  called 
weather  phenomena,  have  their  principal  cause 
in  the  heating  power  of  the  sun's  rays  ;  so  the 
directions  of  the  wind  (partly  on  Lambert's 
proposition)  were  at  an  early  period  compared 
with  the  state  of  the  barometer,  with  variations 
in  temperature,  and  with  differences  in  the  hy- 
grometric  state  of  the  atmosphere.  Tables  of 
the  pressure  of  the  atmosphere  along  with  par- 
ticular winds,  designated  by  the  title  of  baro- 
metrical wind-cards,  have  given  a  deep  insight 
into  the  connection  of  meteorological  phenom- 
ena(35^).  With  wonderful  acumen,  Dove  per- 
ceived, in  the  laws  of  the  rotation  of  the  winds 
of  both  hemispheres,  which  he  discovered,  the 
cause  of  many  grand  variations  (processes)  in 
the  atmospheric  ocean(^^^).  The  thermal  dif- 
ference between  countries  lying  near  the  equa- 
tor and  those  situated  near  the  pole,  engenders 
two  opposite  currents  in  the  upper  regions  of 
the  atmosphere  and  on  the  surface  of  the 
earth.  In  consequence  of  the  diversity  of  the 
rotatory  velocity  in  the  parts  lying  nearer  the 
pole,  or  nearer  the  equator,  the  air  which  is 
streaming  from  the  pole  acquires  an  eastern, 
that  which  is  pouring  along  from  the  equator  a 
western  direction.  From  the  struggle  between 
these  two  currents,  the  place  of  descent  of  the 
higher,  the  alternating  displacements  of  the 
one  by  the  other,  depend  the  most  important 
phenomena  of  atmospheric  pressure,  of  the 
heating  and  cooling  of  the  aerial  strata,  of  the 
precipitation  of  moisture,  and,  indeed,  as  Dove 
has  correctly  shown,  of  the  formation  of  clouds 
and  their  configuration.  The  forms  of  clouds, 
those  all-enlivening  ornaments  of  the  land- 
scape, are  faithful  indications  of  what  is  going 
on  in  the  upper  regions  of  the  air ;  and  in 
calms,  and  floating  in  the  warm  summer's  sky, 
they  are  also  the  "  projected  image"  of  the 
heat-radiating  surface  of  the  ground. 

Where  the  influence  of  the  radiation  of  heat 
is  conditional  on  the  relative  position  of  great 
continental  and  oceanic  surfaces,  as  betwixt  the 
East  coast  of  Africa  and  the  West  coast  of  the 
peninsula  of  Hindostan,  regular  periodical  chan- 
ges in  the  direction  of  the  winds  accompany 
the  changes  in  the  declination  of  the  sun,  and 
constitute  the  Indian  monsoons(^^^),  the  Hippa- 
los  of  the  Greek  navigators.  These  winds 
must  have  been  amongst  the  earliest  regular 
winds  recognized  and  taken  advantage  of  by 
mankind.  In  this  knowledge  of  the  monsoons, 
which  has  certainly  been  spread  over  China 
and  Hindostan,  the  Eastern,  Arabian,  and 
Western  Malayan  Seas,  for  thousands  of  years, 
as  well  as  in  the  still  older  and  more  generally 
diffused  observation  of  the  sea  and  land  breeze, 
lies  the  hidden  germ  of  the  fast-advancing  me- 
teorological science  of  the  present  day.  The 
long  series  of  magnetic  stations  which  have 
now  been  established  from  Moscow  to  Pekin, 
through  the  whole  of  Northern  Asia,  as  they 
have  it  also  in  charge  to  observe  meteorologi- 
cal phenomena  in  general,  will  soon  become  of 


great  importance  in  establishing  the  Law  of 
THE  Winds.  The  comparison  of  observations 
made  simultaneously  at  places  many  hundreds 
of  miles  apart,  will  determine  whether  or  not 
the  same  east  wind  blows  from  the  barren  ta- 
ble-lands of  Gobi  to  the  interior  of  Russia,  or 
whether,  and  at  what  point  in  the  line  of  sta- 
tions, the  direction  of  the  current  becomes 
changed  through  a  descent  of  air  from  the  high- 
er regions.  We  shall  then,  in  the  true  sense 
of  the  phrase,  learn  "  whence  the  wind  cometh." 
If  we  would  base  the  required  result  on  obser- 
vations continued  for  not  fewer  than  twenty 
years,  Mahlman's  careful  notifications  assure 
us  that  in  the  middle  latitudes  of  the  temperate 
zone  in  both  continents  the  west- south-west  is 
the  prevailing  wind. 

Our  knowledge  of  the  distribution  of  heat 
in  the  atmosphere  has  gained,  in  some  respects, 
in  clearness,  since  attempts  have  been  made 
to  connect  the  points  that  indicate  the  mean 
temperature  of  the  year,  of  the  summer  and  of 
the  winter,  by  different  orders  of  lines.  The 
system  of  Isothermal,  Isotheral,  and  Isochim- 
enal  lines,  which  I  first  proposed  in  1817,  may, 
perhaps,  when  it  has  been  gradually  perfected 
by  the  united  efforts  of  natural  philosophers,  be 
found  to  supply  a  general  and  grand  basis  for 
a  comparative  Climatology.  Terrestrial  mag- 
netism first  acquired  a  scientific  shape  when 
scattered  partial  results  were  connected  graph- 
ically with  one  another  by  lines  of  equal  varia- 
tion, of  equal  dip,  and  of  equal  intensity. 

The  expression  Climate,  in  its  most  general 
acceptation,  indicates  every  change  in  the  at- 
mosphere which  sensibly  affects  our  organs — ■ 
temperature,  humidity,  alteration  of  barometri- 
cal pressure  ;  calms  or  storms  of  wind  from  va- 
rious quarters  ;  amount  of  electrical  tension  ; 
purity  of  atmosphere,  or  its  contamination  with 
gaseous  exhalations  more  or  less  pernicious ; 
finally,  degree  of  habitual  transparency  and  se- 
renity of  the  sky,  which  is  not  merely  impor- 
tant in  connection  with  the  amount  of  radia- 
tion from  the  ground,  the  organic  evolution  of 
plants,  and  the  ripening  of  fruits,  but  also  with 
the  feelings  and  whole  mental  estate  of  man- 
kind. 

Were  the  surface  of  the  earth  composed  of 
one  and  the  same  homogeneous  fluid  mass,  or 
of  rocky  strata  of  like  colour,  like  density,  like 
smoothness,  like  capacity  of  absorption  for  the 
sun's  rays,  and  like  power  of  radiation  into 
planetary  space,  then  would  the  Isothermal, 
Isotheral,  and  Isochimenal  lines  run  parallel  to 
one  another,  and  to  the  Equator.  In  such  an 
hypothetical  condition  of  the  earth's  surface, 
the  power  of  absorbing  and  of  emitting  light 
and  heat  would  be  the  same  in  the  same  paral- 
lel of  latitude  all  round  the  globe.  And  it  is, 
in  fact,  from  such  a  mean,  and,  as  it  were,  pri- 
mary condition,  which  neither  excludes  the 
transmission  of  heat  to  the  interior  of  the 
earth,  nor  towards  the  atmosphere  involving 
it,  nor  the  communication  of  heat  by  currents 
of  air,  that  the  mathematical  consideration  of 
climates  sets  out.  All  that  alters  the  absorb- 
ing and  radiating  powers  of  the  surface  in  par- 
ticular parts  lying  in  the  same  parallels  of  lati- 
tude, produces  inflections  in  the  Isothermal 
lines.  The  nature  of  these  inflections,  the 
angle  under  which  the  isothermal,  isotheral, 


THE  ATMOSPHERE— CLIMATE. 


97 


and  isochimenal  lines  cut  the  parallel  circles, 
the  portion  of  the  convexities  or  concavities 
of  these  lines  in  respect  of  the  pole  of  the  cor- 
responding hemisphere,  are  the  effects  of  calo- 
rific or  frigorific  causes  which  show  themselves 
possessed  of  more  or  less  power  under  differ- 
ent geographical  longitudes. 

The  progress  of  Climatology  has  been  favour- 
ed in  a  remarkable  manner  by  the  spread  of 
European  civilization  from  two  opposite  sea- 
boards, by  its  extension  from  our  Western  Eu- 
ropean coast  to  an  Eastern  coast  on  the  other 
side  of  the  great  Atlantic  vallet-  When  the 
British,  after  the  temporary  establishments 
which  had  proceeded  from  Iceland  and  Green- 
land, had  founded  the  first  permanent  colonies 
on  the  shores  of  the  United  States  of  America, 
where  religious  persecution,  fanaticism,  and 
love  of  freedom,  soon  swelled  the  ranks  of  the 
settlers,  the  bold  adventurers  must  have  been 
amazed  at  the  severity  of  the  winters  which 
they  encountered,  from  North  Carolina  and 
Virginia  to  the  River  St.  Lawrence,  in  com- 
parison with  those  which  prevail  under  corre- 
sponding parallels  of  latitude  in  Italy,  France, 
and  Great  Britain.  Such  climatic  observations, 
however  exciting  they  must  have  been,  still 
only  bore  fruits  when  they  could  be  based  on 
numerical  results  of  mean  annual  temperatures. 
If,  between  the  parallels  of  58°  and  30°  N.  lati- 
tude we  compare  Nain,  on  the  coast  of  Labra- 
dor, with  Gottenburg,  Halifax  with  Bordeaux, 
New  York  with  Naples,  St.  Augustin  in  Florida 
with  Cairo,  we  find  the  differences  in  mean  an- 
nual temperature  between  the  East  of  America 
and  the  West  of  Europe,  under  similar  paral- 
lels of  latitude,  progressing  from  north  to  south, 
from  ll°-5,  7° -7  and  3°-8  to  almost  0  Cent. 
The  gradual  decrease  of  difference  in  the  above 
series,  through  28  degrees  of  latitude,  is  very 
remarkable.  Still  farther  to  the  south,  and 
within  the  tropics,  the  isothermal  lines  in  al- 
most every  part  of  both  divisions  of  the  globe 
run  parallel  with  the  equator.  From  the  ex- 
amples here  given,  it  is  obvious  that  the  ques- 
tions we  hear  so  constantly  repeated  in  our 
social  circles,  as  to  how  many  degrees  Amer- 
ica— and  without  any  distinction  of  East  or 
West  coast — is  colder  than  Europe]  and  how 
many  degrees  the  mean  annual  temperature  in 
Canada  and  the  United  States  of  America  is 
lower  than  under  corresponding  parallels  of 
latitude  in  Europe  1  when  taken  as  general  ex- 
pressions, are  totally  without  meaning.  The 
difference  under  each  particular  parallel  is  dif- 
ferent from  what  it  is  under  every  other  paral- 
lel ;  and  without  special  comparisons  of  the 
winter  and  summer  temperatures  of  the  oppo- 
site coasts,  no  right  conception  can  be  formed 
of  the  several  particular  climatic  relations  in 
so  far  as  they  influence  agriculture,  trade,  and 
the  feelings  of  comfort  and  convenience,  or  the 
contrary. 

In  enumerating  the  causes  that  may  produce 
disturbances  in  the  form  of  the  isothermal  lines, 
I  distinguish  the  causes  tending  to  exalt,  and 
the  causes  tending  to  depress  teAperature.  To 
the  first  class  belong :  the  vicinity  of  a  west 
coast  in  the  temperate  zone  ;  the  configuration 
of  a  continent  cut  up  into  numerous  peninsu- 
las ;  deep  bays,  and  far-penetrating  arms  of  the 
sea ;  the  right  position  of  a  portion  of  dry  land 
N 


— i.  c.  its  relatiojis  cither  to  an  ocean  free  from 
ice  which  extends  beyond  the  polar  circle,  or 
to  another  continent  of  considerable  extent 
which  lies  between  the  same  meridional  lines 
under  the  equator,  or,  at  all  events,  in  part 
within  the  tropics  ;  farther,  the  prevalence  of 
southerly  and  westerly  winds  on  the  western 
confines  of  a  continent  in  the  northern  tem- 
perate zone  ;  mountain  chains,  which  serve  as 
screens  against  winds  from  colder  countries  ; 
the  rarity  of  swamps,  which  continue  covered 
with  ice  through  the  spring,  and  even  some 
way  into  summer  ;  the  absence  of  forests  on  a 
dry  sandy  soil  ;  finally,  the  constant  serenity 
of  the  heavens  in  the  summer  months,  and  the 
neighbourhood  of  a  pelagic  stream  of  running 
water  of  a  higher  temperature  than  that  of  the 
surrounding  sea. 

To  the  second  class  of  causes,  or  those  that 
tend  to  depress  the  mean  annual  temperature 
by  exciting  cold,  I  enumerate :  the  elevation  of 
a  place  above  the  sea  level,  without  any  thing 
like  remarkable  elevated  plains  surrounding  it ; 
the  vicinity  of  an  eastern  coast  in  high  and 
middle  latitudes  ;  the  massive  or  unbroken  out- 
line of  a  continent  without  indentation  of  its 
coasts  and  deep  sea  bays  ;  the  wide  extension 
of  the  land  towards  the  poles  up  to  the  region 
of  eternal  ice  (without  the  intervention  of  a 
sea  open  in  winter) ;  a  geographical  position 
in  longitude  of  such  a  kind  that  the  equatorial 
and  tropical  regions  belong  to  the  ocean — in 
other  words,  the  absence  of  a  heating,  radia- 
ting tropical  country  between  the  same  merid- 
ian lines  as  the  country  whose  climate  is  to  be 
determined  ;  mountain  chains  whose  form  and 
direction  are  such  that  they  prevent  the  access 
of  warmer  winds  ;  or  the  neighbourhood  of  iso- 
lated summits  down  whose  slopes  cold  currents 
of  air  descend  ;  extensive  forests,  which  hinder 
the  sun's  rays  from  reaching  the  ground,  whose 
appendicular  organs  (the  leaves),  by  their  vital 
activity,  throw  off  large  quantities  of  watery 
vapour,  and  vastly  increase  the  amount  of  ra- 
diating or  cooling  superficial  surface,  and  so 
act  in  a  threefold  manner — by  shading,  by 
evaporating,  and  by  radiating ;  great  swamps, 
which,  up  to  the  middle  of  summer,  in  the 
north,  form  a  kind  of  subterraneous  glacier  in 
the  flats;  a  misty  or  overcast  summer  sky, 
which  diminishes  the  effect  of  the  sun's  rays 
by  intercepting  them  in  their  passage  to  the 
earth  ;  finally,  a  very  clear  winter's  sky,  by 
which  radiation  is  favoured(2*''). 

The  simultaneous  activity  of  disturbkig, 
whether  heating  or  cooling  causes,  determines 
as  a  total  effect  the  inflexions  of  the  isothermal 
lines  projected  upon  the  surface  of  the  earth, 
their  course  being  especially  influenced  by  the 
relations  of  extent  and  configuration  bettveen 
the  opaque  continental  and  the. fluid  oceanic 
masses.  The  perturbating  causes  engender 
convex  or  concave  summits  of  the  isothermal 
curves.  But  there  are  disturbing  causes  of 
different  orders,  each  of  which  must  first  be 
separately  considered  ;  subsequently,  in  order 
to  ascertain  the  whole  effect  upon  the  motion 
(direction  or  local  curving)  of  the  isothermal 
lines,  it  must  be  discovered  which  of  the  sev- 
eral influences  in  their  combinations  modify, 
annul,  or  strengthen  each  other,  as  happens  in 
the  case  of  other  small  oscillations  that  meet 


98 


THE  ATMOSPHERE— CLIMATE. 


and  intersect  each  other.  Such  is  the  spirit  of 
the  method,  by  which  I  flatter  myself  it  will 
one  day  become  possible  to  connect  immeasu- 
rable series  of  apparently  isolated  facts  with 
one  another,  by  empirical  numerically  expressed 
laws,  and  to  demonstrate  the  necessity  of  their 
mutual  dependence. 

As  we  find  westerly  or  west-south-westerly 
winds  in  both  temperate  zones  as  the  prevail- 
ing counter-currents  to  the  trades  or  east  winds 
of  the  tropics,  and  as  these,  to  a  country  with 
an  eastern  sea-board,  are  land  winds,  and  to  a 
country  with  a  western  sea-board  again  are 
sea  winds  (z.  e.  as  they  blow  over  a  level,  which 
by  reason  of  its  mass  and  the  descent  of  the 
cooled  particles  of  water  is  susceptible  of  no  | 
great  degree  of  chilling)  ;  so  comes  it  that, 
where  oceanic  currents  running  near  the  shore  ' 
do  not  influence  the  temperature,  the  east 
coasts  of  continents  are  colder  than  the  west 
coasts.  Cook's  junior  companion  in  his  second 
voyage,  the  gifted  George  Forster,  whom  I  have 
to  thank  for  urging  me  on  to  various  extensive 
undertakings,  was  the  first  who  directed  par- 
ticular attention  to  the  difference  of  tempera- 
ture of  the  east  and  west  coasts  in  both  hemi- 
spheres, as  well  as  to  the  correspondence  be- 
tween the  temperature  of  the  west  coasts  of 
North  America  in  the  middle  latitudes,  with 
that  of  the  west  of  Europe  within  the  same 
parallels(3"). 

Accurate  observations  show  a  striking  differ- 
ence even  in  pretty  high  northern  latitudes 
between  the  mean  annual  temperature  of  the 
east  and  west  sea-boards  of  America.  At  Nain 
in  Labrador  (57°  10'  N.  lat.)  this  temperature 
is  3°  8  C  [5°16  F.]  under  the  freezing  point  of 
water  [i.  e.  26°-8  F.],  whilst  at  New  Archangel 
on  the  north-west  shore  of  Russian  America 
(57''  3'  N.  lat.)  it  is  still  6°-9  C.  [12°-4  F.]  above 
the  freezing  point  [i.  e.  44° -4  F.].  At  the  first 
named  place  the  mean  summer  temperature 
scarcely  reaches  6° -2  C.  [43°  1  F.],  whilst  at 
the  second  it  is  as  high  as  13°-8  C.  [56°-5  F.]. 
The  mean  winter  temperature  of  Pekin  (39°  54' 
N.  lat.)  is  at  least  3°  C.  below  the  freezing  point ; 
whilst  in  the  west  of  Europe,  even  at  Paris 
(48°  50'  N.  lat.),  it  is  fully  3° -3  C.  above  this 
point.  The  mean  winter  cold  of  Pekin  is  thus 
lower  by  2°  5  C.  than  that  of  Copenhagen, 
which  lies  17  degrees  of  latitude  farther  to  the 
north. 

We  have  already  spoken  of  the  extreme 
slowness  with  which  the  great  masses  of  the 
ocean  follow  alterations  in  the  temperature  of 
the  air,  and  how  in  virtue  of  this  property  the 
ocean  acts  as  an  equalizer  of  temperature.  It 
tempers  at  once  the  rudeness  of  the  winter's 
cold  and  the  fervour  of  the  summer's  heat. 
Frohi  hence  a  second  important  contrast :  the 
difference  between  the  insular  or  sea-board  cli- 
mates which  all  deeply  indented  continents 
abounding  in  bays  and  peninsulas  enjoy,  and 
the  climates  of  the  interior  of  great  masses  of 
terra  firma.  This  remarkable  contrast,  in  the 
variety  of  its  phenomena,  in  its  influence  on 
the  power  of  vegetation,  and  the  improvement 
of  agriculture,  on  the  transparency  of  the  at- 
mosphere, the  radiation  of  the  earth's  surface 
and  the  height  of  the  line  of  perpetual  snow, 
was  first  fully  developed  in  the  writings  of 
Leopold  von  Buch.    In  the  interior  of  the  Asi- 


atic continent,  Tobolsk,  Barnaul  on  the  Obi 
and  Irkutsk,  have  summers  like  those  of  Ber- 
lin, Munster  and  Cherbourg  in  Normandy  ;  but 
these  summers  are  followed  by  winters  in  which 
the  coldest  month  reaches  the  fearful  mean 
temperature  of  from  —18°  to —20°  C.  [0°  4  to 
— 4^  F.].  In  the  summer  months,  again,  the 
thermometer  for  weeks  together  is  seen  stand- 
ing at  30°  and  31°  C.  [86°  and  87°-8  F.].  Such 
continental  climates  are  therefore  well  and  prop- 
erly characterized  as  excessive  by  Buffon,  who 
was  so  well  versed  both  in  mathematics  and 
in  physics  ;  artd  the  inhabitants  of  the  countries 
where  they  prevail,  seem  doomed,  like  the  un- 
fortunates in  Dante's  Purgat()ry("'^), 

"  a  soffrir  tormenti  caldi  e  geli."* 

In  no  quarter  of  the  globe,  not  even  in  the 
Canary  Islands  or  in  Spain,  or  the  South  of 
France,  have  I  met  with  more  delicious  fruit, 
particularly  more  beautiful  grapes,  than  in  As- 
trachan,  near  the  shores  of  the  Caspian  Sea 
(46°  21'  N.  lat.).  With  a  mean  annual  temper- 
ature of  about  9°  C.  [about  48^°  F.],  the  mean 
summer  temperature  rises  to  21°-2  C.  [70°1 
F.],  equal  to  that  of  Bordeaux  ;  whilst  not  only 
there,  but  still  farther  to  th«  south,  at  Kislar 
on  the  mouth  of  the  Texel,  in  the  latitudes  of 
Avignon  and  Rimini,  the  thermometer  in  the 
winter  season  sinks  to  — 25°  and  — 30°  C. 
[—13°  and  —22°  F.] 

Ireland,  Guernsey  and  Jersey,  the  Peninsula 
of  Brittany,  the  coasts  of  Normandy,  and  the 
South  of  England,  in  the  mildness  of  their  win- 
ters and  the  low  temperature  and  overcast  sky 
of  their  summers,  present  the  most  remarkable 
contrasts  with  the  continental  climate  of  the 
interior  of  the  east  of  Europe.  In  the  north- 
east of  Ireland  (54°  56'  N.  lat.),  under  the  same 
parallel  as  Konigsberg  in  Prussia,  the  myrtle 
grows  as  vigorously  as  it  does  in  Portugal. 
Th&  month  of  August,  the  temperature  of 
which  in  Hungary  is  21°  C,  is  scarcely  16°  C. 
in  Dublin,  which  stands  on  the  same  isother- 
mal line  of  9P  ;  and  the  mean  winter  temper- 
ature, which  sinks  in  Buda  to  — 2°-4  C,  in 
Dublin  (with  its  mean  annual  temperature, 
lower  by  9°  C.)  is  still  4° -3  above  the  freezing 
point  of  water  ;  i.  e.,  it  is  2°  C.  higher  than  in 
Milan,  Pavia,  Padua,  and  the  whole  of  Lom- 
bardy,  where  the  mean  annual  temperature  is 
fully  12°-7  C.  At  Stromness  in  the  Orkneys, 
not  half  a  degree  further  to  the  south  than 
Stockholm,  the  mean  winter  temperature  is  4° 
C,  higher  consequently  than  that  of  Paris,  and 
nearly  equal  to  that  of  London.  Even  in  the 
Faro  Islands  in  62°  N.  latitude,  the  influence 
of  the  westerly  winds  and  of  the  ocean  is  such, 
that  the  water  of  the  inland  lakes  never  free- 
zes. On  the  pleasant  coasts  of  Devonshire, 
where  Salcombe,  by  reason  of  its  mild  climate, 
has  been  called  the  Montpellier  of  the  North, 
the  Agave  Mexicana  has  been  seen  flowering 
in  the  open  air,  and  Oranges,  trained  as  espa- 
liers, and  scarcely  protected  for  a  few  weeks 
with  mats,  have  borne  fruit.  There,  as  well 
as  at  Penzance  and  Gosport,  and  Cherbourg 
on  the  NoriAn  coast,  the  mean  winter  tem- 
perature is  as  high  as  5°-5  C,  that  is  to  say, 
but  l°-3  below  the  temperature  of  the  corre- 

[*  "  From  beds  of  raging  fire  to  starve  in  ice." 

Milton,  after  Dant\ 
thongh  the  English  poet  )ays  the  scene  in  his  Hell.— T»,l 


THE  ATMOSPHERE— CLIMATE. 


99 


Bponding  season  in  Montpellier  and  Flor- 
ence("^).  The  relations  now  indicated  show 
how  important  for  vegetation,  agriculture,  the 
growth  of  fruit,  and  the  feeling  of  climatic  com- 
fort is  the  distribution  of  the  same  annual  mean 
temperature  over  the  different  seasons  of  the 
year.* 

The  lines  which  I  have  entitled  isochimenal 
and  isotheral  (lines  of  like  mean  winter  and 
summer  heat)  are  by  no  means  parallel  with 
the  isothermal  lines  (lines  of  like  mean  annual 
heat).  If  in  places  where  the  Myrtle  grows 
untended,  and  the  ground  in  winter  is  never 
permanently  covered  with  snow,  the  tempera- 
ture of  the  summer  and  autumn  is  still  just  suf- 
ficient— nay,  it  might  be  said,  is  barely  suffi- 
cient to  bring  the  apple  to  perfect  ripeness  ;  if 
the  vine,  when  it  yields  drinkable  wine,  flies 
islands,  and  almost  all  sea-boards,  even  those 
with  a  western  exposure  ;  the  cause  of  this 
does  not  alone  reside  in  the  lower  summer 
temperature  of  the  coasts,  which  our  thermom- 
eter in  the  shade  proclaims  ;  it  lies  in  the  hith- 
erto so  little  considered,  and  yet  in  other  phe- 
nomena (such  as  an  explosion  of  a  mixture  of 
chlorine  and  hydrogen  gas)  so  important  dis- 
tinction between  direct  and  diffused  light  with 
a  clear  or  clouded  state  of  the  heavens.  It  is 
long  since  I  directed  the  attention  of  the  ob- 
servers of  natural  phenomena  and  of  botanical 
physiologists  to  these  distinctions,  as  well  as 
to  the  unestimated  heat  locally  developed  in 
the  vegetable  cell  under  the  influence  of  direct 
Iight(36*). 

If  we  descend  in  the  thermal  scale  of  hus- 
bandry of  different  kinds(^"),  beginning  with 
the  hottest  climates,  where  Vanilla,  Cacao,  the 
Banana,  Plantain,  and  Cocoanut  Palm  are  suc- 
cessfully cultivated,  to  the  regions  in  succes- 
sion of  the  Pine-apple,  Sugar-cane,  Coffee, 
Date,  Cotton-tree,  Citron,  Olive,  true  Chestnut, 
and  Vine  yielding  drinkable  wine,  the  careful 
geographical  consideration  of  the  limits  of  each 
of  these  species  of  culture,  respect  being  had 
at  once  to  the  plain  and  to  the  mountain  slope, 
assures  us  that  other  climatic  relations  than 
those  connected  with  the  mean  annual  temper- 
ature here  come  into  play.  To  take  the  single 
instance,  of  the  vine,  I  remind  my  reader,  that 
in  order  to  have  palatable  wine('*^),  not  only 
must  the  mean  annual  temperature  exceed  9^° 
C.  [49°-55  F.],  but  that  the  mean  winter  cold 
must  not  fall  quite  to  the  freezing  point  (0°-5 
C,  33°-4  F.),  and  this  must  be  followed  by  a 
mean  summer  heat  of  at  least  18°  C.  [64°-4  F.]. 
At  Bordeaux,  in  the  valley  of  the  Garonne 
(North  latitude  44°  50'),  the  temperature  of  the 
year,  of  the.  winter,  of  the  summer,  and  of  the 
autumn,  are  respectively  13°-8;  6°-2  ;  21°-7; 
and  14°-4.  In  the  plains  of  the  Baltic,  where 
wine  is  grown  that  is  not  palatable,  though  it 
is  nevertheless  consumed,  the  corresponding 
numbers  are  8°-6  ; —°7;  17°-6;  and  8°-6.  If 
it  seem  strange  that  the  great  differences  which 
the  cultivation  of  the  vine,  favoured  or  opposed 
by  climate,  exhibits,  are  not  more  conspicuous- 
ly shown  by  our  thermometrical  numbers,  this 
strangeness  will  be  lessened  by  the  considera- 


[*  For  a  great  deal  of  interesting  information  on  temper- 
ature the  reader  is  referred  to  an  excellent  "  Thermomet- 
rical Table,"  by  Alfred  S.  Taylor,  published  by  Willatt,  98 
Cheapside.  It  is  a  complete  Encyclopedia  of  Thermotics. 
— Tk.] 


tion,  that  a  thermometer  set  for  observation  in 
the  shade,  and  as  effectually  as  possible  pro- 
tected from  the  effects  of  direct  insolation  and 
nocturnal  radiation,  does  not  by  any  means 
give  the  true  superficial  temperature  for  every 
division  of  the  year,  under  periodical  variations 
of  the  heat  of  the  ground,  exposed  to  the  whole 
amount  of  insolation  [and  of  radiation]. 

In  the  same  way  as  the  milder,  more  equa- 
ble climate  of  the  peninsula  of  Brittany  stands 
related  to  the  climate  of  the  rest  of  the  com- 
pact continent  of  France,  colder  in  winter,  hot- 
ter in  summer,  so  to  a  certain  extent  does  the 
climate  of  Europe  stand  related  to  that  of  the 
general  continent  of  Asia,  to  which  Europe 
forms,  in  fact,  a  kind  of  western  peninsula. 
Europe  owes  its  milder  climate :  to  the  geo- 
graphical position  of  Africa,  which  in  its  vast 
extent,  favouring  the  ascending  current  of  air, 
presents  a  solid  radiating  surface  within  the 
tropics,  whilst  southward  from  Asia  the  equa- 
torial region  is  mostly  oceanic  ;  to  its  parti- 
tions and  vicinity  to  the  sea — its  forming  the 
western  boundary  of  the  northern  part  of  the 
Old  World  ;  to  the  existence  of  a  sea  free  from 
ice,  where  it  extends  towards  the  north.  Eu- 
rope from  this  would  become  colder  were  Af- 
rica to  be  overflowed  by  the  sea  and  to  disap- 
pear(^^^) ;  were  the  Mythical  Atlantis  to  arise 
and  connect  Europe  with  North  America ; 
were  the  gulf-stream  to  cease  from  flowing 
and  pouring  its  tepid  current  into  the  northern 
sea,  or  were  another  continent,  raised  by  vol- 
canic forces,  to  intervene  between  the  Scandi- 
navian peninsula  and  Spitzbergen.  If  we  see 
the  mean  annual  temperature  of  Europe  sink- 
ing as  we  proceed  along  the  same  parallel  of 
latitude  from  the  shores  of  the  Atlantic,  from 
France,  through  Germany,  Poland,  and  Russia, 
towards  the  Ural  Mountains,  from  west  to  east, 
therefore,  the  principal  cause  of  the  phenome- 
non is  to  be  sought  for  in  the  progressively  less 
and  less  subdivided  or  more  compact  form  of 
the  land  as  the  longitude  increases,  in  the  in- 
creasing remoteness  of  the  tempering  ocean, 
as  iti  the  feebler  influence  of  the  west  wind. 
Beyond  the  Ural  chain  the  west  becomes  the 
chilling  land-wind,  for  then  it  is  blowing  over 
extensive  tracts  of  country  covered  with  ice 
and  snow.  The  intense  cold  of  Western  Sibe- 
ria is  greatly  connected  with  such  relations  of 
configuration  in  the  land  and  of  currents  of 
air(^^'*),  nowise,  as  Hippocrates  and  Trogus 
Pompeius  presumed,  and  as  distinguished  trav- 
ellers in  the  18th  century  have  gone  on  fancy- 
ing, with  great  elevation  of  the  country  above 
the  level  of  the  sea. 

If  we  pass  on  from  the  consideration  of  di- 
versities of  temperature  in  the  plains,  to  ine- 
qualities in  the  polyhedral  configuration  of  the 
surface  of  our  planet,  we  contemplate  the 
mountains  either  according  to  their  influence 
on  the  climate  of  the  neighbouring  low  lands, 
or  according  to  the  influences  which  they  ex- 
ert, in  consequence  of  hypsometrical  relations, 
upon  their  own  summits,  frequently  spread  out 
into  lofty  plateaus  or  table-lands.  The  group- 
ing of  mountains  into  chains  divides  the  sur- 
face of  the  earth  into  different  basins,  some- 
times into  narrow  circular  valleys  surrounded 
by  lofly  walls — circus-like  cauldrons,  which  (as 
in  Greece  and  a  portion  of  Asia  Minor)  give  in- 


100 


THE  ATMOSPHERE. 


dividual  local  characters  to  the  climate  in  re- 
spect of  warmth,  dampness,  frequency  of  winds 
and  storms,  and  transparency  of  atmosphere. 
These  circumstances  hare  from  time  immemo- 
rial exerted  a  powerful  influence  upon  the  na- 
ture of  the  productions  of  the  soil,  and  on  the 
manners,  forms  of  government,  and  likings  and 
dislikings  of  neighbouring  races  for  one  anoth- 
er. The  character  of  the  geographical  individ- 
uality reaches  its  maximum,  as  it  were,  where 
the  diversities  in  the  configuration  of  the  sur- 
face, both  in  the  vertical  and  the  horizontal  di- 
rection, in  the  relief  and  the  partitioning  of  con- 
tinents, are  the  greatest  possible.  With  such 
relations  of  the  soil  are  contrasted  the  steppes 
of  Northern  Asia,  the  grassy  plains  (Prairies, 
Savannas,  Llanos,  and  Pampas)  of  the  New 
Continent,  the  heaths  or  moors  of  Europe,  and 
the  sandy  and  rocky  deserts  of  Africa. 

The  law  of  the  decrement  of  temperature  ac- 
cording to  the  height  above  the  sea  under  dif- 
ferent parallels  of  latitude,  is  one  of  the  most 
important  particulars  in  connection  with  the 
knowledge  of  meteorological  processes,  with 
the  geographical  distribution  of  plants,  the  theo- 
ry of  terrestrial  refraction,  and  the  various  hy- 
potheses which  bear  upon  the  determination  of 
the  height  of  the  atmosphere.  In  the  course 
of  the  numerous  mountain  expeditions  I  have 
undertaken,  both  within  and  without  the  trop- 
ics, the  determination  of  this  law  has  always 
been  one  of  the  principal  objects  of  my  obser- 
vations and  experiments(^"). 

Since  the  true  relations  of  thermal  distribu- 
tion over  the  surface  of  the  earth,  i.  e.,  the  in- 
flections of  the  isothermal  and  isotheral  lines, 
and  the  unequal  distances  of  these  from  each 
other  in  the  several  systems  of  eastern  and 
western  temperature  of  Asia,  mid-Europe,  and 
North  America,  have  been  studied  and  made 
more  generally  known,  we  must  not  any  long- 
er inquire,  even  in  a  general  way,  what  frac- 
tional part  of  the  mean  annual  or  summer  tem- 
perature corresponds  to  a  change  of  one  de- 
gree of. geographical  latitude  1  In  each  system 
of  isothermal  lines  of  like  curvature  there  pre- 
vails an  intimate  and  necessary  connection  be- 
tween three  elements :  the  decrease  of  tem- 
perature in  the  perpendicular  direction  from 
below  upwards  ;  the  difference  of  temperature 
in  changing  the  place  of  observation  by  1°  of 
latitude  ;  the  equality  of  the  mean  tempera- 
ture of  a  mountain  station,  and  the  polar  dis- 
tance of  a  point  laid  down  on  the  level  of  the 
sea. 

In  the  East  American  system,  the  mean  an- 
nual temperature  changes  from  the  coasts  of 
Labrador  to  Boston  for  every  degree  of  lati- 
tude by  0°-88  C. ;  from  Boston  to  Charleston 
by  0°-95  C.  ;  from  Charleston  to  the  tropic  of 
Cancer  in  Cuba  onwards,  the  change,  however, 
becomes  less — there  it  is  only  0°-66  C.  With- 
in the  tropics  the  change  is  still  smaller,  the  va- 
riation from  Havanna  to  Cumana,  correspond- 
ing to  a  degree  of  latitude,  being  no  more  than 
0°  20  C. 

It  is  quite  different  in  the  system  of  iso- 
therms of  mid-Europe.  Between  the  parallels 
of  38°  and  71  °  I  find  the  decrease  of  temperature 
to  coincide  very  accurately  with  half  a  degree 
(0°-5  C.)  for  each  degree  of  latitude.  But,  as 
in  this  country,  the  fall  in  temperature  is  1°  C. 


for  every  480,  or  523  feet  of  perpendicular  rise, 
it  follows  that  here  a  rise  of  from  240  to  262 
feet  above  the  level  of  the  sea  corresponds,  in 
respect  of  temperature,  to  one  degree  of  lati- 
tude. The  mean  annual  temperature  of  the 
Convent  on  Mount  St.  Bernard,  7,668  feet 
above  the  sea-level,  in  latitude  46°  50',  would 
thus  be  met  with  again  in  the  plain,  in  latitude 
75°  50'. 

In  that  part  of  the  chain  of  the  Andes  which 
lies  within  the  tropics,  my  observations,  which 
have  been  carried  out  to  an  elevation  of  18,000 
feet,  indicate  a  fall  of  1°  C.  for  96  toises,  or  576 
feet ;  my  friend  Boussingault,  thirty  years  later, 
found  90  toises,  or  540  feet,  as  the  mean  corre- 
sponding to  the  same  fall.  On  comparing  the  pla- 
ces which  stand  among  the  Cordilleras  at  equal 
heights  above  the  sea,  whether  on  the  slopes 
themselves,  or  on  the  extensive  plateaus  which 
they  form,  I  found  an  increase  of  from  l°-6  to 
2°-3  C.  in  mean  annual  temperature  of  the  lat- 
ter over  the  former.  Without  the  cooling  ef- 
fects of  nocturnal  radiation,  the  difference 
would  be  still  greater.  As  the  climates  are 
there  stratified,  as  it  were,  superposed  in  lay- 
ers from  the  Cacao  groves  of  the  lowlands  up 
to  the  line  of  perpetual  snow,  and  as  the  tem- 
perature in  the  tropical  zone  varies  but  very 
slightly  in  the  course  of  the  whole  year,  a  tol- 
erably fair  idea  is  formed  of  the  relations  in 
respect  of  temperature  to  which  the  inhabi- 
tants of  the  great  cities  of  the  Andes  are  ex- 
posed, when  these  relations  are  compared  with 
the  temperature  of  particular  months  in  the 
plains  of  France  and  Italy.  Whilst  the  tem- 
perature of  the  day  on  the  wooded  banks  of  the 
Orinoco  is  such  that  it  exceeds,  by  4°  C,  that 
of  the  month  of  August  at  Palermo,  we  find 
when  we  have  ascended  the  mountains  to  Po- 
payan  (911  toises),  that  we  are  in  the  tem- 
perature of  the  three  summer  months  at  Mar- 
seilles ;  in  Quito,  again  (1493  toises),  the  tem- 
perature is  that  of  the  end  of  the  month  of 
May  at  Paris,  and  when  we  have  attained  the 
Paramos  or  mountain  wilds,  overgrown  with 
dwarf  Alpine  plants,  still  bearing  large  flowers 
(1800  toises),  we  meet  with  the  temperature  of 
the  beginning  of  the  month  of  April  at  Paris. 

The  acute  Peter  Martyr  de  Anghiera,  one  of  JSt 
the  friends  of  Christopher  Columbus,  was  the  |H 
first  who  perceived  (in  the  expedition  of  Rod- 
rigo  Enrique  Colmenares,  Oct.  1510),  that  the 
snow-line  always  rises  higher  the  nearer  the 
equator  is  approached.  I  find  these  words  in 
the  beautiful  work,.  De  Rebus  Oceanicis(2'"') : 
"  The  River  Gaira  comes  from  a  mountain  (in 
the  Sierra  Nevada  de  Santa  Marta),  which, 
from  the  reports  of  the  companions  of  Colme- 
nares, is  higher  than  any  mountain  yet  discov- 
ered. It  must  undoubtedly  be  so,  if,  in  a  zone 
which  is  at  most  10°  from  the  equinoctial  line, 
it  retains  its  covering  of  snow  continually." 
The  inferior  limit  of  the  eternal  snow  in  a  given 
latitude  is  the  summer  limit  of  the  snow-line  ; 
that  is,  the  maximum  height  to  which  the 
snow-line  recedes  in  the  course  of  the  entire 
year.  From  this  summer  limit  of  the  snow- 
line, three  other  phenomena  must  be  distin- 
guished :  Annual  fluctuations  of  the  snow-line ; 
occasional  or  sporadic  falls  of  snow ;  and  gla- 
ciers, which  appear  to  be  peculiar  to  the  tem- 
perate and  frigid  zones,  on  which  Saussure's 


THE  ATMOSPHERE. 


101 


fmraortal  work  on  the  Alps,  and  in  later  years 
the  labours  of  Venetz,  of  Charpentier,  and  of 
Agassiz,  endowed  with  perseverance  that  set 
rtanger  at  naught,  have  thrown  much  interest- 
ing and  new  light. 

We  know  only  the  inferior,  not  the  superior, 
boundary  of  the  eternal  snow  ;  for  the  mount- 
ains of  the  earth  do  not  rise  into  the  ethereal 
or  Olympic  empyrean,  into  the  thin  dry  strata 
of  the  atmosphere,  which  we  may  presume 
with  Bouguer  no  longer  contain  any  vesicular 
vapour  turned  into  crystals  of  ice,  and  thus 
made  visible.  The  lower  snow-limit,  howev- 
er, is  not  merely  a  function  of  the  geographical 
latitude,  or  the  mean  annual  temperature  ;  the 
tropics,  even  the  equator  itself,  is  not  the  sit- 
uation, as  was  long  believed  and  taught,  where 
the  snow-limit  attains  its  highest  elevation 
above  the  level  of  the  sea.  The  phenomenon 
which  we  here  advert  to  is,  in  fact,  an  ex- 
tremely complicated  one,  and  depends  general- 
ly on  various  relations  of  temperature,  moist- 
ure, and  mountain  configuration.  If  these  re- 
lations themselves  be  subjected  to  a  more  spe- 
cial analysis,  as  a  great  number  of  new  meas- 
urements permit  us  to  do(^"),  we  discover  as 
coefficient  causes  determining  the  snow-line  : 
Differences  in  temperature  of  the  different  I 
seasons  of  the  year ;  direction  of  the  prevail-  I 
ing  winds,  and  their  contact  with  the  sea  and  ! 
land ;  the  degree  of  dryness  or  moistness  of 
the  upper  strata  of  the  atmosphere ;  the  abso- 
lute magnitude  or  thickness  of  the  deposited 
and  accumulated  snow ;  the  relation  of  the 
snovi^y  summit  to  the  total  height  of  the  mount- 
ain ;  the  relative  position  of  the  particular 
mountain  considered  in  the  chain  ;  the  steep- 
ness of  the  declivities ;  the  vicinity  of  other 
mountains  likewise  capped  with  perpetual 
snow  ;  the  extent,  lay,  and  height  of  the  plain 
or  level  from  which  the  snowy  mountain  rises 
isolated,  or  as  one  in  a  group  or  chain,  and 
which  may  be  a  sea-coast,  or  the  interior 
of  a  continent,  covered  with  wood,  or  with  a 
thick  short  turf,  which  may  be  sandy,  barren, 
and  strewn  with  naked  rocks,  or  a  wet  mossy 
bottom. 

While  the  snow-line  in  South  America  reach-  i 
es  a  height  under  the  equator  which  equals  j 
that  of  the  summit  of  Mont  Blanc,  and  in  the  i 
high  lands  of  Mexico,  near  the  northern  tropic, 
in    19°   North   latitude,  according  to    recent 
measurements,  descends  from  that  by  a  quan- 
tity equal  to  about  960  feet,  it  rises,  according 
to  Pentland,  in  the  southern  tropical  zone  (lat.  j 
up  to  18^  south),  and  in  the  western  or  Chil-  ' 
ian  Andes,  not  in  the  eastern  chain,  to  more 
than  2500  feet  higher  than  it  is  under  the  equa- 
tor, on  Chimborazo,  Cotopaxi,  and  Antisana, 
not  far  from  Quito.     Dr.  Gillies  states,  indeed, 
that  much  farther  to  the  south,  namely,  on  the 
declivity  of  the  volcanic  mountain  Penguenes 
(33°  S.  lat.),  he  found  the  snow-line  at  an  ele- 
vation between  2270  and  2350  toises  above  the 
level  of  the  sea.   The  evaporation  of  the  snow, 
in  consequence  of  the  radiation  into  an  atmo- 
sphere which  is  excessively  dry  in  summer, 
into  skies  which  are  scarcely  obscured  by  a 
cloud,  is  so  rapid,  that  the  volcano  of  Aconca- 
gua, to  the  north-east  of  Valparaiso  (lat.  32^° 
south),  which  was  found  by  the  Expedition  of 
the  Beagle  to  be  more  than  1400  feet  higher 


than    Chimborazo,  was   once    seen   without 
snow(3"). 

In  almost  the  same  parallel  of  North  lati- 
tude (30J°to  31°),  the  snow-limit  of  the  south- 
ern slopes  of  the  Himalaya  is  found  nearly  at 
the  elevation  which  various  combinations  and 
comparisons  might  lead  us  to  expect,  viz., 
12,180  feet;  on  the  northern  slopes,  however, 
under  the  influence  of  the  lofty  table-land  of 
Thibet,  the  mean  height  of  which  appears  to 
be  10,800  feet,  the  snow-limit  is  only  met  with 
at  an  elevation  of  15,600  feet.  This  phenom- 
enon, which  has  often  been  the  subject  of  dis- 
cussion both  in  Europe  and  in  India,  on  the 
cause  of  which  I  have  myself  made  known  my 
views  in  several  papers(3^^),  possesses  more 
than  a  merely  physical  interest ;  it  has  had  an 
important  influence  upon  the  state  of  numerous 
tribes  of  mankind.  Meteorological  processes 
fit  or  unfit  extensive  districts  of  a  continent  for 
agriculture  or  pasturage. 

As  with  the  temperature  the  quantity  of  va- 
pour contained  in  the  atmosphere  increases, 
this,  which  is  so  important  an  element  for  the 
whole  of  the  organic  creation,  varies  with  the 
hour  of  the  day,  the  season  of  the  year,  the  de- 
gree of  latitude,  and  the  height  above  the  level 
of  the  sea.  The  recent  experience  so  general- 
ly obtained  through  the  use  of  August's  Psy- 
chrometer,  according  to  the  ideas  of  Dalton 
and  Daniell,  for  the  determination  of  the  rela- 
tive moistness  of  the  air  by  means  of  the  dif- 
ference between  the  dew-point  and  the  tem- 
perature of  the  air,*  has  considerably  increased 
the  extent  of  our  knowledge  of  the  hygromet- 
rical  relations  of  the  surface  of  the  earth.  Tem- 
perature, atmospheric  pressure,  and  quarter  of 
the  wind,  all  stand  in  most  intimate  connec- 
tion with  the  vivifying  moisture  of  the  air. 
This  vivification,  however,  is  not  so  much  a 
consequence  of  the  quantity  of  vapour  held  dis- 
solved under  different  latitudes,  as  of  the  man- 
ner and  frequency  of  its  precipitation  in  the 
shape  of  dew,  fog,  rain,  or  snow,  which  moist- 
ens the  ground.  From  the  deduction  of  the 
gyratory  law  of  winds  by  Dove,  and  the  views 
of  this  distinguished  philosopher(^^*),  it  appears 
that  in  our  northern  zone  "the  elasticity  of  va- 
pour is  greatest  with  south-west,  least  with 
north-east  winds.  On  the  west  side  of  the 
wind-card  it  diminishes,  and  on  the  contrary  it 
rises  on  the  east  side.  On  the  west  side,  viz., 
the  colder,  heavier,  drier  current,  forces  back 
the  warmer,  lighter,  much  moister  air  ;  whilst 
on  the  east  side  the  former  is  overcome  by  the 
latter.  The  south-west  current  is  the  pene- 
trating equatorial  stream ;  the  north-east  the 
sole  prevaihng  polar  current." 

The  beauty  and  fresh  verdure  of  many  trees 
which  grow  in  countries  within  the  tropics, 
where  for  five,  six,  or  seven  months  together 
there  is  never  a  cloud  to  be  seen  on  the  face 
of  the  heavens,  where  no  visible  dew  or  rain 
ever  falls,  inform  us  that  the  appendages  of  the 
stem  or  the  leaves  have  the  power,  in  virtue 
of  a  peculiar  vital  process,  which  perhaps  is 
not  one  merely  producing  cold  by  radiation,  of 

[*  Now  very  conveniently  obtained  by  the  different  read- 
ings of  two  thermometers,  as  like  each  other  as  possible, 
one  of  which  has  its  balb  dry,  the  other  its  bulb  wet.  The 
instrument  is  commonly  sold  under  the  name  of  Mason's 
Hy^ometer  in  England.— Tb.] 


102 


THE  ATMOSPHERE. 


withdrawing  water  from  the  atmosphere.  With 
the  parched  levels  of  Cumana,  Coro,  and  Cea- 
ra,  in  North  Brazil,  the  deluges  of  rain  which 
fall  in  other  districts  of  tropical  countries  con- 
trasts strongly  :  for  example,  in  Havana,  where 
observations  carried  on  for  six  years  by  Ramon 
de  la  Sarga  show  the  mean  annual  fall  of  rain 
to  amount  to  102  Parisian  inches — four  or  five 
times  as  much  as  it  is  in  Paris  or  Geneva(^"). 
On  the  slopes  of  the  Andes,  the  quantity  of 
rain  that  falls,  like  the  temperature,  diminishes 
with  the  height(3").  It  was  found  by  my  com- 
panion in  my  South  American  journey,  M.  Cal- 
das,  of  Santa  Fe  de  Bogota,  not  to  exceed  37 
inches  at  a  height  of  8200  feet,  which  is  but 
little  more  than  the  quantity  that  falls  on  some 
of  the  west  coasts  of  Europe.  At  Quito,  when 
the  temperature  was  from  12°  to  13°  C,  Bous- 
singault  sometimes  saw  Saussure's  hygrome- 
ter recede  to  26°  ;  and  in  his  great  aerostatic 
ascent  Gay  Lussac  saw  the  same  instrument 
at  25° -3,  his  elevation  at  the  time  being  6600 
feet,  and  the  temperature  of  the  air  4° -6  C. 
The  greatest  degree  of  dryness  yet  observed  in 
a  low  country  was  seen  by  Gustavus  Rose, 
Ehrenberg,  and  myself,  between  the  valleys  of 
the  Irtisch  and  Obi,  in  Northern  Asia.  In  the 
Platowskaja  Steppe,  after  the  south-west  wind 
had  been  long  blowing  from  the  interior  of  the 
continent,  the  temperature  of  the  air  being 
23°-7  C,  we  found  the  dew-point  4°-3  below 
the  freezing-point.  The  air  only  contained  JA^ 
of  watery  vapour(3").  Several  able  observers, 
Kaemtz,  Bravais,  and  Martins,  have  of  late 
years  called  in  question  the  great  degree  of 
dryness  of  the  mountain  air,  which  seemed  to 
follow  from  Saussure's  observations  among  the 
Alps,  and  my  own  among  the  heights  of  the 
Cordilleras.  The  relative  moistness  of  the  air 
in  Zurich  was  contrasted  with  that  of  the  air 
of  the  Faulhorn,  a  mountain  which  indeed  could 
only  be  called  high  in  Europe(^'^).  The  moist- 
ure with  which  the  peculiar  species  of  large- 
flowered,  myrtle-leaved  Alpine  shrubs  are  al- 
most perpetually  bedewed  in  the  region  of  the 
Paramos  of  the  tropical  Andes,  betvi^een  11,000 
and  12,000  feet  above  the  sea  level,  and  not  far 
from  the  line  where  snow  begins  to  fall,  does 
not,  however,  necessarily  imply  a  great  abso- 
lute moistness  of  the  air  in  this  region  ;  like 
the  frequent  fogs  in  the  beautiful  plateau  of 
Bogota,  it  only  proclaims  the  frequency  of  pre- 
cipitations. Banks  of  fog  at  these  heights  form 
and  disappear  several  times  in  the  course  of 
an  hour  when  the  air  is  calm  ;  such  rapid  chan- 
ges characterize  the  lofty  plateaus  and  paramos 
of  the  Andes. 

The  ELECTRICITY  OP  THE  ATMOSPHERE,  Wheth- 
er considered  in  the  lower  regions  or  in  the 
cloudy  canopy  aloft,  viewed  problematically  in 
its  silent  periodical  diurnal  progression,  or  in 
the  brilliant  and  noisy  explosions  of  the  thun- 
der-storm, stands  in  manifold  relationship  with 
all  the  phenomena  of  thermal  distribution,  of 
atmospheric  pressure  and  its  disturbances,  of 
hydrometeors,  and  apparently  also  of  the  mag- 
netism of  the  outer  crust  of  the  earth.  It  ex- 
erts a  most  powerful  influence  upon  the  whole 
of  the  animal  and  vegetable  world,  and  this  not 
merely  through  the  meteorological  processes, 
precipitations  of  watery  vapour,  of  acids,  or  of 
ammoniacal  compounds,  which  it  occasions, 


but  also  immediately  as  the  electrical  force, 
that  force  which  excites  the  nerves  and  occa- 
sions or  assists  the  circulation  of  the  juices. 
This  is  not  the  place  to  renew  the  contest  in 
regard  to  the  source  of  the  electricity  of  the 
serene  sky,  which  has  at  one  time  been  ascri 
bed  to  the  evaporation  of  impure  fluids,  i.  e.  flu- 
ids loaded  with  earths  and  sdlts(3"),  at  another 
to  the  growth  of  vegetables(3'*°),  or  other  chem- 
ical decompositions  proceeding  on  the  surface 
of  the  earth,  to  the  unequal  distribution  of  heat 
in  the  different  strata  of  the  atmosphere(3*^), 
finally,  according  to  Peltier's  able  inquiries(^^'), 
to  the  influence  of  a  constantly  negative  charge 
of  the  globe.  Limited  to  the  results  which 
electrometrical  observations,  particularly  those 
which  the  clever  arrangement  of  an  electro- 
magnetical  apparatus,  first  proposed  by  Colla- 
don,  have  given.  Physical  Cosmography  ought 
to  indicate  the  unquestionable  increase  of  the 
general  positive  aerial  electricity  with  the  height 
of  the  station  and  freedom  from  surrounding 
trees(^"^),  its  daily  ebb  and  flow  (according  to 
Clarke's  Dublin  experiments,  in  more  intricate 
periods  than  Saussure  and  I  had  detected),  and 
its  differences  according  to  season,  distance 
from  the  equator,  and  the  continental  or  oceanic 
nature  of  the  surface. 

If  the  electrical  equilibrium,  on  the  whole,  be 
less  disturbed  where  the  atmosphere  is  resting 
on  the  sea  than  on  the  land,  it  is  the  more  re- 
markable to  observe  how  small  clusters  of  isl- 
ands surrounded  by  an  extensive  ocean  act 
upon  the  state  of  the  atmosphere  and  give  oc- 
casion to  thunder-storms.  In  fogs,  and  at  the 
beginning  of  falls  of  snow,  I  have  in  the  course 
of  a  long  series  of  observations  seen  the  pre- 
vious permanent  vitreous,  change  suddenly  into 
the  resinous  electricity,  and  these  alternate  re- 
peatedly, as  well  in  the  plains  of  the  frigid  zone 
as  under  the  tropics  in  the  Paramos  or  Alpine 
wildernesses  of  the  Cordilleras  between  10,000 
and  12,000  feet  high.  The  alternate  transition 
was  in  all  respects  similar  to  that  which  the 
electrometer  had  shown  shortly  before  during 
the  continuance  of  a  thunder-storm(^**).  When 
the  vesicles  of  vapour  have  become  aggregated 
into  clouds  with  determinate  outlines,  the  elec- 
trical tension  of  the  outer  layer  or  surface(2**) 
upon  which  the  electricity  of  the  insulated  ve- 
sicular vapour  overflows,  increases  with  the 
measure  of  the  condensation.  Slate-gray  col- 
oured clouds,  according  to  Peltier's  Paris  ex- 
periments, have  resinous,  white,  rose,  and 
orange-coloured  clouds,  have  vitreous  electri- 
city. Thunder  clouds  not  only  involve  the 
highest  summits  of  the  Andes,  (I  have  myself 
observed  the  vitrifying  effects  of  lightning  on 
one  of  the  rocky  crags  which  rise  from  the  cra- 
ter of  the  Volcano  of  Toluca,  14,300  feet  high), 
but  storm  clouds  have  been  measured,  which 
were  floating  over  low  lands  in  the  temperate 
zone,  at  a  vertical  height  of  25,000  feetC^"). 
Occasionally,  however,  the  thundering  and 
lightning  stratum  of  cloud  descends  to  an  alti- 
tude of  five,  and  even  of  three  thousand  feet 
from  the  ground. 

According  to  Arago's  experiments,  the  most 
comprehensive  we  yet  possess  upon  this  diffi- 
cult portion  of  meteorology,  there  are  dischar- 
ges of  lightning  of  three  kinds  :  zig-zag  or  fork- 
ed lightnings,  sharply  defined  on  their  edges  ; 


ORGANIC  LIFE. 


lightnings  that  illuminate  whole  clouds,  which 
seem  to  open  up  at  once  ;  lightning  in  the  form 
of  fire-ballsC^"').  If  the  two  first  of  these 
scarcely  last  for  the  -j-^i^  of  a  second,  the  glob- 
ular kind  of  lightning,  on  the  contrary,  moves 
much  more  slowly,  and  continues  visible  for 
several  seconds.  Occasionally — and  late  ob- 
servations confirm  the  description  of  the  phe- 
nomenon already  given  by  Nicholson  and  Bec- 
caria  —  single  clouds  show  themselves  high 
above  the  horizon,  which,  without  audible  thun- 
der, without  any  appearance  of  a  storm,  con- 
tinue steadily  luminous  for  a  long  time  both  in 
the  interior  and  around  the  edges  ;  hail-stones, 
drops  of  rain,  and  flakes  of  snow,  have  also 
been  observed,  which  were  luminous  as  they 
fell,  without  any  precursory  thunder-storm. 

In  the  geographical  distribution  of  storms, 
the  coasts  of  Peru,  in  which  it  never  thunders 
or  lightens,  present  the  most  remarkable  con- 
trast with  all  the  rest  of  the  tropical  zones  be- 
sides, in  which  at  certain  seasons  of  the  year, 
four  or  five  hours  after  the  culmination  of  the 
sun,  thunder-storms  occur  almost  every  day. 
From  the  concurring  testimony  of  northern  nav- 
igators —  Scoresby,  Parry,  Ross,  Franklin— 
which  has  been  collected  by  Arago,  it  is  im- 
possible to  doubt  that  in  high  northern  latitudes, 
such  as  the  parallels  from  70°  to  75°,  electrical 
explosions  are  extremely  rareC^^**). 

The  meteorological  portion  of  our  Delinea- 
tion of  Nature,  which  we  here  conclude,  shows 
that  all  the  processes— absorption  of  light,  ev- 
olution of  heat,  alteration  of  elasticity,  hygro- 
metrical  state  and  electrical  tension,  which  the 
immeasurable  atmospheric  ocean  presents,  are 
so  intimately  connected,  that  each  individual 
meteorological  process  is  simultaneously  modi- 
fied by  any  one,  or  by  all  the  others.  These 
varied  disturbances,  which  involuntarily  re- 
mind us  of  those  that  the  nearer  and  particu- 
larly the  smaller  of  the  heavenly  bodies,  the 
satellites,  comets,  and  shooting  stars,  experi- 
ence in  their  course  through  space,  render  the 
interpretation  of  the  complex  meteorological 
processes  difficult ;  they  circumscribe,  and,  for 
the  most  part,  make  impossible,  the  prediction 
of  atmospherical  changes,  which  for  horticul- 
ture and  agriculture,  for  navigation  and  the  en- 
joyment and  pleasure  of  existence,  would  be 
so  important.  Those  who  place  the  value  of 
meteorology  not  in  a  knowledge  of  the  subject 
itself,  but  in  such  problematical  prognostica- 
tions, are  penetrated  with  the  belief  that  this 
portion  of  natural  science,  on  account  of  which 
so  many  journeys  have  been  made  into  remote 
mountainous  countries  of  the  globe,  cannot 
boast  of  any  advance  for  centuries.  The  con- 
fidence which  they  refuse  to  natural  philoso- 
phers, they  yield  to  the  changes  of  the  moon, 
and  to  certain  famous  days  in  the  calendar. 

"  Great  departures  from  the  usual  distribu- 
tion of  mean  temperature  seldom  occur  locally ; 
they  are,  for  the  most  part,  relatively  shared 
in  by  extensive  districts  of  country.  The 
amount  of  departure  is  a  maximum  at  one  par- 
ticular spot,  from  which  it  diminishes  to  the 
confines  around.  If  these  confines  be  exceed- 
ed, great  variations  in  the  opposite  sense  are 
forthwith  discovered.  Like  constitutions  of 
the  weather  are  more  frequently  observed  from 


South  to  North  than  from  West  to  East.  The 
maximum  cold  of  the  end  of  1829,  (when  I  con- 
cluded my  Siberian  travels),  occurred  at  Berlin, 
whilst  North  America  enjoyed  an  unusual  mild- 
ness of  season.  It  is  an  entirely  arbitrary  as- 
sumption to  suppose  that  a  hot  summer  follows 
a  cold  winter,  or  that  a  mild  winter  succeeds  a 
cool  summer'X^^').  The  states  of  the  weather  in 
neighbouring  lands — two  corn  and  wine-grow- 
ing countries,  for  example,  often  so  varied  and 
so  opposite,  produce  the  most  beneficial  effects 
in  equalizing  the  prices  of  agricultural  produce 
rn  each.  It  has  been  well  observed,  that  the 
barometer  alone  informs  us  of  what  is  going  on 
in  respect  of  alterations  in  the  pressure  of  the 
whole  of  the  strata  of  air  above  the  place  of 
observation,  even  to  the  extreme  limits  of  our 
atmosphere,  whilst  the  thermometer  and  hy- 
grometer only  report  upon  the  local  tempera- 
ture and  moistness  of  the  lower  stratum  in  con- 
tact with  the  surface.  We  only  conclude  as  to 
the  thermometrical  and  hygroscopical  modifica- 
tions of  the  upper  strata,  where  immediate  ob- 
servations made  on  mountains  or  in  aerostatic 
journeys  are  wanting,  from  hypothetical  com- 
binations, so  that  the  barometer  may  likewise 
come  to  serve  both  as  a  thermometer  and  hy- 
grometer. Important  changes  in  the  state  of 
the  weather  are  not  owing  to  any  merely  local 
cause  at  the  place  of  observation  itself;  they 
are  usually  consequences  of  a  condition  which 
has  begun,  through  perturbation  in  the  equilibri- 
um of  the  currents  of  air,  at  a  vast  distance, 
and,  for  the  major  part,  not  at  the  surface  of 
the  earth,  but  in  the  highest  regions  :  bringing 
hither  cold  or  warm,  dry  or  moist  air,  impair- 
ing or  increasing  the  transparency  of  the  at- 
mosphere, changing  the  piled  masses  of  cumu- 
lus-clouds into  the  light  and  feathery  cirrus. 
Inaccessibility  of  phenomena  thus  allying  it- 
self to  multiplicity  and  complexity  of  perturba- 
tions, it  has  always  appeared  to  me,  that  me- 
teorology must  seek  her  welfare  and  her  roots 
in  the  torrid  zone ;  in  that  favoured  region 
where  the  same  winds  always  blow,  where  the 
ebb  and  flow  of  the  atmospheric  pressure,  the 
course  of  hydrometeors,  and  the  occurrence  of 
electrical  explosions,  are  periodically  and  reg- 
ularly recurrent. 

Having  now  passed  through  the  entire  circuit 
of  the  inorganic  life  of  the  earth,  and  delinea- 
ted our  planet  with  a  few  leading  touches,  in 
its  configuration,  its  internal  heat,  its  electro- 
magnetical  charge,  its  luminous  processes  at 
either  pole,  and  its  internal  or  volcanic  reac- 
tion upon  the  solid  and  variously  compounded 
crusts  ;  having,  finally,  considered  the  phenom- 
ena of  its  double  outer  covering,  the  ocean  and 
the  atmosphere,  our  Picture  of  Nature,  accord- 
ing to  the  older  ideas  of  Physical  Geography, 
might  be  held  as  finished.  But  when  the  phil- 
osophic view  essays  to  reach  a  hig:her  point, 
the  delineation  would  seem  to  want  its  attract- 
ive features,  did  it  not  at  the  same  time  pre- 
sent the  sphere  of  Organic  Life  in  the  numer- 
ous grades  of  its  typical  developments.  The 
idea  of  animation  is  so  closely  connected  with 
the  idea  of  the  existence  of  the  impelling,  cease- 
lessly active,  decompounding,  compounding, 
and  fashioning  natural  forces,  which  inhere  in 
the  terrestrial  ball,  that  in  the  popular  Mythus 


4|p4  ORGANIC  LIFE. 

of  the  nations  of  antiquity,  the  production  of 
plants  and  animals  was  always  ascribed  to  these 
forces  ;  the  state  of  the  surface  of  our  planet, 
when  it  was  unoccupied  by  life,  was  even  re- 
ferred to  the  chaotic  pmneval  ages  of  the  con- 
flicting elements.  To  the  empirical  domain  of 
objective  sensuous  consideration,  to  the  delin- 
eation of  That  which  has  become,  or  of  the  ac- 
tual state  and  condition  of  our  planet,  the  mys- 
terious and  unresolved  problem  of  Things  be- 
coming does  not  rightfully  belong. 

Our  description  of  the  world,  abiding  soberly 
by  reality,  remains  a  stranger,  not  from  timid- 
ity, but  from  the  nature  of  the  subject  and  its 
limits,  to  the  obscure  history  of  the  beginning 
of  organized  things(^"') ;  the  word  history  being 
here  taken  in  its  most  usual  acceptation.  But 
in  our  account  of  the  actual  Universe,  we  may 
direct  attention  to  the  fact,  that  in  the  inorgan- 
ic crust  of  the  earth,  the  same  elementary  sub- 
stances are  present  which  enter  into  and  com- 
pose the  organic  frames  of  plants  and  animals. 
We  may  say,  that  the  same  powers  prevail  in 
these  as  in  those,  which  combine  and  separate 
bodies,  which  give  consistency  and  fluidity  in 
the  organic  tissues :  but,  subjected  to  condi- 
tions which,  not  yet  fathomed,  have  been 
systematically  grouped  according  to  analogies 
more  or  less  happily  imagined,  under  the  very 
indefinite  titles  of  effects  of  the  vital  force.  It 
is,  therefore,  felt  as  a  want,  in  the  frame  of 
mind  which  leads  us  to  look  on  nature  with  a 
contemplative  eye,  that  we  pursue  the  physical 
phenomena  which  present  themselves  to  us  on 
earth  to  their  very  farthest  limits,  to  the  evo- 
ultion  of  vegetable  forms,  and  the  discovery 
of  that  which  in  the  organisms  of  animals  is 
endowed  with  self-motive  force.  In  this  way 
does  the  geographical  distribution  of  things  or- 
ganically-animated, i.  e.,  plants  and  animals, 
connect  itself  with  the  delineation  of  the  inor- 
ganic natural  phenomena  of  the  body  of  the 
globe. 

Without  pretending  in  this  place  to  discuss 
the  difficult  question  of  "  the  self-motive"  in 
animals,  i.  e.,  the  difference  between  animal 
and  vegetable  life,  we  must  first  direct  atten- 
tion to  the  circumstance  that,  were  we  endow- 
ed by  nature  with  a  microscopic  eye,  and  were 
the  integuments  of  plants  completely  transpa- 
rent, the  world  of  vegetation  would  not  meet 
us  with  that  aspect  of  immobility  and  repose 
in  which  it  now  presents  itself  to  our  senses. 
The  interiors  of  the  cellular  structures  of  vege- 
tables are  ceaselessly  animated  by  the  most  di- 
versified currents,  rotatory,  rising  and  falling, 
dividing  and  ramifying,  or  altering  their  direc- 
tion— as  is  made  manifest  by  the  movement  of 
the  granular  sap-corpuscles  in  the  leaves  of 
several  water-plants  (Najades  Characeae,  Hy- 
drocharideae),  and  in  the  hairs  of  phaneroga- 
mous land-plants ;  there  is  at  the  same  time 
seen  a  confused,  molecular  movement,  first  ob- 
served by  the  distinguished  botanist,  Robert 
Brown,  but  which  also  occurs  among  finely-di- 
vided particles  of  matter  of  all  kinds,  the  phe- 
nomenon not  taking  place  only  within  organic 
cells  ;  the  circular  movement  of  the  globules 
of  the  cambium,  in  a  system  of  special  vessels 
(cyclosis) ;  lastly,  the  singular  articulated  fili- 
form vessels  of  the  anthers  of  the  Chara  and 
the  reproductive  organs  of  the  liverworts  and 


sea-weeds  which  have  the  faculty  of  uncoiling 
themselves,  and  in  which  Meyen,  snatched  too 
soon  away  from  science,  believed  that  he  rec- 
ognized the  analogues  of  the  spermatozoa  of 
the  animal  creation.  If  to  the  multifarious  ex- 
citements and  movements  we  add  those  that 
belong  to  endosmose  and  the  processes  of  nu- 
trition and  growth,  and  farther  to  the  penetra- 
tion [and  exhalation]  of  air,  we  have  a  picture 
of  the  forces  which,  almost  unknown  to  us,  are 
active  in  the  silent  life  of  the  vegetable  world. 

Since  I  first  portrayed  the  universal  life  of 
the  surface  of  the  earth,  and  the  distribution 
of  organic  forms,  both  in  the  line  of  the  height 
and  of  the  depth,  in  my  "  Views  of  Nature," 
our  knowledge  in  this  direction  also  has  been 
surprisingly  increased  by  Ehrenberg's  brilliant 
discoveries,  "on  the  demeanor  of  minute  life 
in  the  ocean  as  well  as  in  the  ice  of  the  polar 
lands,"  discoveries  made  not  by  the  way  of  in- 
duction, but  by  that  of  simple  accurate  observa- 
tion. The  sphere  of  vitality,  we  might  almost 
say  the  horizon  of  life,  has  extended  itself  be- 
fore our  eyes.  "  There  is  not  only  an  invisibly 
small,  or  microscopical,  incessantly  active  life 
in  the  neighbourhood  of  both  poles,  where  lar- 
ger organisms  are  no  longer  produced  ;  but  the 
microscopical  forms  of  life  of  the  South  Polar 
Sea,  collected  in  the  Antarctic  Voyage  of  Sir 
James  Ross,  comprise  a  wonderful  variety  of  en- 
tirely new  and  often  extremely  beautiful  forms. 
Even  in  the  remains  of  the  liquefied  round- 
ed masses  of  ice  that  were  picked  up  swim- 
ming about  under  the  latitude  of  78°  10",  more 
than  fifty  species  of  silicious-shelled  polygas- 
trica,  coscinodisca,  with  their  green  ovaries, 
and  consequently  living  and  successfully  strug- 
gling with  the  extreme  of  severe  cold,  were 
discovered.  In  the  bay  of  the  Erebus,  in  from 
1242  to  1620  feet  of  water,  sixty-eight  silicious- 
shelled  polygastrica  and  phytolitharia,  and  with 
them  only  a  single  calcareous-shelled  polytha- 
lamium,  were  drawn  up  by  means  of  the  lead. 

The  oceanic  microscopic  forms  have  hitherto 
been  in  vastly  preponderating  proportion  of  the 
silicious-shelled  kinds,  although  sihca  does  not 
appear  among  the  constituents  of  sea-water  dis- 
covered by  analysis,  and  the  earth  can  only  be 
well  conceived  as  mixed  with  or  suspended  in 
the  waters.  The  ocean,  however,  is  not  only 
in  particular  spots,  and  in  arms  and  bays,  or 
near  the  shore,  thickly  peopled  with  invisible, 
i.  e.,  by  the  unassisted  eye,  unseen  living  at- 
oms ;  it  may  be  assumed,  from  the  samples  of 
water  drawn  to  the  south  of  the  Cape  of  Good 
Hope,  under  57°  S.  latitude,  as  well  as  from 
the  middle  of  the  Atlantic,  under  the  tropics, 
by  Schayer,  in  his  return  from  Van  Diemen's 
Land,  that  in  its  ordinary  state,  without  shown 
ing  any  particular  colour,  without  being  filled 
with  floating  fragments  of  the  silicious-shelled 
filaments  of  the  genus  Chaetoceros,  which  so 
much  resemble  the  Oscillatoria  of  our  fresh 
waters,  but  when  perfectly  transparent  to  the 
naked  eye,  the  ocean  still  contains  numerous 
independent  microscopical  organisms.  Sever- 
al polygastrica  from  Cockburn  Island,  mixed 
with  the  excrements  of  Penguins  and  sand,  ap- 
pear to  be  spread  over  the  whole  earth  ;  oth- 
ers, again,  are  common  to  either  pole(^"). 

From  this  (and  all  the  more  recent  observa 
tions  confirm  the  view)  it  appears  that  in  the 


ORGANIC  LIFE. 


105 


eternal  night  of  the  depths  of  ocean,  animal  life 
especially  prevails,  whilst  upon  continents,  ve- 
getable life,  which  requires  the  periodic  stimu- 
lus of  the  ^un's  rays,  is  the  more  extensively 
diffused.  Considered  with  reference  to  mass, 
the  vegetable  far  exceeds  the  animal  world  on 
the  face  of  the  globe.  What  is  the  number  of 
great  cetaceans  and  pachydermatous  tribes,  in 
comparison  with  the  bulk  of  the  thick-set  trunks 
of  lofty  trees,  from  eight  to  twelve  feet  in  di- 
ameter, that  grow  in  the  forests  of  the  tropical 
zone  of  South  America,  between  the  Orinoco, 
the  Amazon's  River,  and  the  Rio  de  Madeira  ! 
Even  allowing  the  character  of  the  several 
countries  of  the  earth  to  depend  on  the  aspect 
of  external  phenomena  at  large  ;  if  the  outline 
of  mountains,  the  physiognomy  of  plants  ana 
animals,  the  blue  of  the  sky,  the  contour  of  the 
clouds,  and  the  transparency  of  the  atmosphere 
produce  the  general  impression,  still  it  is  not 
to  be  denied  that  the  principal  element  in  this 
impression  is  the  vegetable  covering  of  the  sur 
face.  The  animal  kingdom  wants  mass,  and 
the  motions  of  individuals  withdraw  them  fre- 
quently from  our  sight.  The  vegetable  world 
works  upon  our  imagination  by  the  mere  force 
of  quantity  ;  its  mass  indicates  its  age  ;  and  in 
vegetables  alone  are  age  and  the  expression  of 
inherent  power  of  renovation  associated(^'2). 
In  the  animal  kingdom — and  this  consideration 
is  also  the  result  of  Ehrenberg's  discoveries — 
it  is  precisely  the  life  that  we  are  wont  to  des- 
ignate as  the  smallest  in  point  of  room,  which 
by  its  subdivision  and  rapid  increase(^")  pre- 
sents the  most  remarkable  relations  in  respect 
of  mass.  The  smallest  of  the  Infusoria,  the 
Monadae,  only  obtain  a  diameter  of  g^^^^th  of  a 
line,  yet  do  these  silicious-shelled  organisms, 
in  moist  countries,  compose,  by  their  accumu- 
lation, subterraneous  strata  several  fathoms  in 
thickness. 

The  impression  of  an  all-animated  nature,  so 
exciting  and  so  salutary  *o  feeling  man,  belongs 
to  every  zone ;  but  it  is  mo.st  powerfully  pro- 
duced towards  the  equator,  in  the  peculiar  zone 
of  the  palms,  the  bamboos,  and  the  arborescent 
ferns — in  regions  where,  from  sea  shores  cov- 
ered with  molluscs  and  corals,  the  ground  rises 
in  stages  to  the  line  of  eternal  snow,  and  the 
relations  of  plants  and  animals,  in  respect  of 
local  position,  embrace  almost  every  height  and 
every  depth.  Organic  forms  even  descend  into 
the  interior  of  the  earth,  and  occur  not  merely 
in  places  where,  through  the  operations  of  the 
miner,  great  excavations  have  been  made  ;  in 
natural  cavities,  also,  which  have  been  opened 
for  the  first  time  by  blasting,  and  to  which  me- 
teoric water  alone  could  have  penetrated  through 
fissures,  I  have  found  the  snowy  stalactitic 
walls  covered  with  the  delicate  reticulations 
of  anUsnea.  Podurellae  penetrate  into  the  icy 
circles  of  the  glaciers  of  Monte  Rosa,  of  the 
Grindelwald,  and  the  Upper  Aar.  Chioncea 
arenoides,  described  by  Dalman,  and  the  mi- 
croscopic Discerea  nivalis,  or  Protococcus,  as 
it  used  to  be  called,  lives  among  the  snows  of 
the  polar  regions  as  well  as  of  our  loftier  mount- 
ains. The  red  colour  of  old  snow  was  known 
to  Aristotle,  and  was  probably  observed  by  him 
among  the  mountains  of  Macedonia(39*).  Whilst 
upon  the  lofty  summits  of  the  Swiss  Alps,  Le- 
cideas,  Parmelias,  and  Umbilicarias  alone,  and 
O 


sparingly,  tint  the  rocks  left  bare  of  snow,  in  the 
elevated  regions  of  the  tropical  Andes,  at  the 
height  of  14,000  and  14,400  feet  above  the  lev- 
el of  the  sea,  single  specimens  of  beautiful 
phanerogamous  plants  are  still  encountered — 
the  tomentose  Calcitium  rufescens,  Sida  Pi- 
chinchensis,  and  Saxifraga  Boussingaulti.  Hot 
springs  contain  small  insects  —  Hydroporua 
thermalis,  Galionellae,  Oscillatoria,  and  Confer- 
vas ;  they  even  irrigate  the  roots  of  phaneroga- 
mous plants.  As  water,  earth,  and  air  are  peo- 
pled by  animated  beings  at  the  most  dissimilar 
temperatures,  so  also  is  the  interior  of  the  most 
dissimilar  parts  in  the  bodies  of  animals  inhab- 
ited. Animated  organisms  have  been  found  in 
the  blood  of  the  frog,  salmon,  &,c.  According 
to  Nordmann,  the  whole  of  the  fluids  of  the 
fish's  eye  are  often  filled  with  a  suctorial  worm 
<Diplostomum) ;  and  in  the  gills  of  the  brasse 
lives  that  extraordinary  double  animal,  denomi- 
nated by  the  naturalist  just  mentioned  the  Di- 
plozoon  paradoxum  ;  a  creature  consisting,  as  it 
seems,  of  two  perfect  animals,  grown  cross- 
wise together,  having  two  heads  and  two  cau- 
dal extremities. 

Granting  the  existence  of  meteoric  infusoria, 
as  they  have  been  called,  to  be  more  than  doubt- 
ful, still  the  possibility  must  not  be  denied,  that 
as  the  pollen  of  the  pine-tree  has  fallen  year 
after  year  from  the  air,  so  may  minute  infuso- 
ry  animalcules  be  passively  raised  with  the  wa- 
tery vapour,  and  floated  for  a  season  in  the  at- 
i  mosphere(^").  This  circumstance  deserves  to 
be  taken  into  serious  consideration,  in  connec- 
tion with  the  old  dispute  in  regard  to  sponta- 
neous generation(^^^),  (generatio  spontanea) ; 
all  the  more,  since  Ehrenberg,  as  already  ob- 
served above,  has  discovered  in  the  kind  of 
dust-rain  which  navigators  frequently  encoun- 
ter in  the  neighbourhood  of  the  Cape  de  Verd 
Islands,  at  a  distance  of  380  sea  miles  from  the 
coast  of  Africa,  the  remains  of  eighteen  spe- 
cies of  silicious  shelled  polygastric  animalcules. 

The  exuberance  of  organisms  whose  distri- 
bution in  space  is  studied  in  the  geography  of 
plants  and  animals,  is  considered  either  accord- 
ing to  the  diversity  and  relative  number  of  the 
types  of  formation,  according  to  the  configura- 
tion of  the  existing  genera  and  species,  or  ac- 
cording to  the  number  of  the  individuals  which 
each  particular  species  presents  upon  a  given 
superficial  area.  Among  plants,  as  among  an- 
imals, it  is  an  important  distinction  in  their 
mode  of  life,  whether  they  are  met  with  singly 
or  living  in  company.  The  species  which  I 
have  designated  social  plants(^^')  cover  large 
tracts  of  country  with  one  unvarying  growth. 
To  this  class  belong  many  species  of  sea-weed 
in  the  ocean,  Cladoniae  and  Musci  in  the  waste 
levels  of  Northern  Asia,  Grasses  and  tubular 
looking  Cactuses,  Avicennia  and  Mangrove  in 
the  tropical  world,  forests  of  coniferous  trees  and 
birches  in  the  Baltic  and  Siberian  plains(35«). 
This  kind  of  geographical  distribution  of  plants, 
along  with  the  individual  aspect  of  the  species, 
their  size,  the  form  of  their  leaves  and  flowers, 
determines  in  an  especial  manner  the  physi- 
ognomical character  of  a  country.  The  shift- 
ing image  of  animal  life,  so  varied  and  attract- 
ive, appealing  so  immediately  to  our  feelings 
of  liking  or  disgust,  remains  almost  wholly  for- 
eign, or  at  least  is  much  less  powerfully  felt,  in 


106 


ORGANIC  LIFE. 


connexion  with  the  members  of  the  vegetable 
kingdom.  Agricultural  nations  increase  arti- 
ficially the  domain  of  various  social  plants,  and 
so  increase  the  aspect  of  uniformity  presented 
by  nature  in  several  districts  of  the  temperate 
and  northern  zones  ;  they  also  root  out  and  de- 
stroy various  wild-growing  plants,  and  unin- 
tentionally propagate  others  that  follow  man  in 
his  wanderings.  The  luxuriant  zone  of  the 
tropical  world  resists  more  powerfully  this  for- 
cible metamorphosis  of  creation. 

Observers  who  have  perambulated  extensive 
districts  of  country  in  short  intervals  of  time, 
who  have  ascended  mountain  ranges  in  which 
the  climates  lie  stratified  one  over  another, 
must  soon  have  been  awakened  to  the  regular 
distribution  of  vegetable  forms.  They  coUect- 
ed  the  raw  material  of  a  science  whose  name 
was  not  yet  pronounced.  The  same  zones  or 
regions  of  plants  which  Cardinal  Bembo(399),  in 
the  16th  century,  when  yet  a  youth,  described  as 
occurring  on  the  slopes  of  Etna,  were  found  re- 
peated on  Mount  Ararat,  by  Tournefort,  who 
acutely  compared  the  Alpine  floras  with  the 
floras  of  plains  under  different  latitudes ;  and 
who  first  remarked  that  the  elevation  of  the 
ground  above  the  level  of  the  sea  in  mountain- 
ous districts  influences  the  distribution  of  plants 
in  the  same  way  as  distance  from  the  pole  in 
plains.  Menzel,  in  an  unedited  Flora  of  Japan, 
incidentally  used  the  expression  Geography  of 
Plants.  This  phrase  again  recurs  in  the  fan- 
tastic but  pleasant ''  Studies  of  Nature"  of  Ber- 
nardin  de  St.  Pierre.  But  the  scientific  treat- 
ment of  the  subject  commenced  wiien  the  dis- 
tribution of  plants  was  viewed  in  close  connex 
ion  with  the  doctrine  of  the  distribution  of  heat 
over  the  surface  of  the  earth  ;  when  plants 
were  arranged  into  natural  orders,  and  it  was 
thus  made  possible  to  distinguish  numerically 
the  particular  forms  which  increase  or  diminish 
from  the  equator  towards  the  poles,  to  per- 
ceive, in  the  different  regions  of  the  earth,  in 
what  numerical  relationship  each  family  stands 
to  the  whole  of  the  mass  of  phanerogamous 
vegetables  which  are  there  indigenous.  It  is 
one  of  the  fortunate  events  in  my  life,  that  at 
the  time  when  I  was  giving  my  attention  al- 
most exclusively  to  botany,  my  studies  should 
have  been  directed  to  the  subject  of  inquiry 
just  mentioned,  by  the  spectacle  of  nature  on 
the  grandest  scale,  and  offering  the  strongest 
contrasts  in  respect  of  climate. 

The  geographical  distribution  of  animal 
forms,  upon  which  Buffon  first  advanced  gen- 
eral, and,  for  the  major  part,  very  accurate 
views,  has  in  recent  times  had  great  assist- 
ance from  the  progress  of  vegetable  geography. 
The  curvatures  of  the  isothermal,  and  particu- 
larly of  the  isochimenal  lines,  are  displayed  in 
the  limits  which  certain  species  of  plants,  and 
of  animals  that  do  not  roam  far  towards  the 
north  or  towards  the  tops  of  snow-covered 
mountains,  seldom  exceed.  The  Elk,  g.  g., 
lives  in  the  Peninsula  of  Scandinavia,  almost 
ten  degrees  farther  to  the  north  than  in  the  in- 
terior of  Siberia,  where  the  lines  of  like  win- 
ter temperature  are  so  remarkably  concave. 
Plants  wander  or  migrate  in  the  egg,  in  the 
seed.  The  seeds  of  many  species  are  provi- 
ded with  peculiar  organs  for  far  journeys 
through  the  air.    Once  rooted,  they  are  more 


dependent  on  the  soil  and  the  temperature  of 
the  atmosphere  which  surrounds  them.  Ani- 
mals widen  at  will  the  circle  of  their  presence 
from  the  equator  towards  the  pole,  and  partic- 
ularly in  regions  where  the  isotheral  lines  arch 
out  towards  the  north,  where  hot  summers  suc- 
ceed the  severest  winters  :  royal  tigers,  which 
do  not  differ  from  those  of  India,  roam  every 
summer  in  Northern  Asia  to  the  latitudes  of 
Berlin  and  Hamburg,  as  Ehrenberg  and  I  have 
shown  in  another  place(*''°). 

The  groups  or  associations  of  vegetable  spe- 
cies which  we  are  accustomed  to  designate 
Flor^  (spheres  or  domains  of  vegetation), 
appear  to  me,  from  what  I  have  seen  o^  the 
earth,  by  no  means  to  reveal  the  prevalence  of 
individual  families  to  such  an  extent  as  au- 
thorizes us  to  establish  geographical  regions  of 
the  Umbellatae,  Solidagineae,  Labiatae,  or  Sci- 
tamineae.  My  particular  views  differ  in  this  re- 
spect fropi  those  of  several  of  my  friends  among 
the  most  distinguished  botanists  of  Germany. 
The  character  of  the  Floras  in  the  high  lands 
of  Mexico,  New  Granada,  Quito,  European 
Russia,  and  Northern  Asia,  consists,  as  I  be- 
lieve, not  in  the  relatively  larger  number  of 
species  which  one  or  two  natural  families  ex- 
hibit, but  rather  in  the  much  more  complex  re- 
lations of  the  aggregate  life  of  many  families, 
and  the  relative  numerical  value  of  their  spe- 
cies. In  meadow  and  steppe  districts  Gram- 
ineaj  and  Cyperaceaj  are  the  prevailing  fami- 
lies ;  in  our  northern  woods  we  meet  especial- 
ly with  Coniferse,  Cupuliferae,  and  Betulineae  ; 
but  this  prevalence  of  form  is  only  apparent, 
and  deceptive  by  reason  of  the  mass  of  the  So- 
cial plants  arresting  the  eye.  The  north  of 
Europe,  and  Siberia  in  the  zone  northward 
from  the  Altai,  no  more  deserve  the  title  of  a 
realm  of  grasses  or  cone-bearing  trees,  than 
the  endles  Llanos  between  the  Orinoco  and 
the  mountain  chain  of  Caraccas  or  the  pine 
forests  of  Mexico.  In  the  associated  life  of 
the  vegetable  forms  which  partly  replace  one 
another,  in  their  relative  numbers  and  group- 
ing, lies  the  aggregate  impression  of  richness 
and  variety,  or  of  poverty  and  monotony  of 
vegetable  nature. 

In  this  brief  consideration  of  the  phenomena 
of  organized  beings,  I  have  ascended  from  the 
simplest  cell(*°'),  and  so,  from  the  first  breath 
of  life,  to  higher  and  higher  forms.  "  The  ag- 
gregation of  mucus-granules  into  a  definitely 
formed  cell-germ,  around  which  a  membrane 
in  form  of  a  vesicle  being  developed,  it  is  con- 
nected into  a  closed  cell,"  is  either  effected  by 
a  pre-existing  cell,  so  that  cell  arises  from 
cell(*°='),  or  the  evolution  of  cells  is  involved 
in  the  obscurity  of  a  chemical  process,  as  in 
the  case  of  the  torula  cerevisiae,  or  yeast  fun- 
gus. The  most  mysterious  subject  of  Incipien- 
cy  can  only  be  lightly  touched  upon  here.  The 
geography  of  organized  beings — plants  and  ani- 
mals— treats  of  the  germs  already  developed, 
of  their  habitats  from  migrations  effected  on 
purpose  or  accidentally,  of  their  respective  re- 
lations, and  their  aggregate  distribution  over 
the  surface  of  the  earth. 

The  general  delineation  of  nature,  which  I 
here  endeavour  to  present,  would  remain  in- 
complete, were  I  not  to  yield  to  the  disposition 
I  feel,  with  a  few  touches,  to  portray  the  hu- 


ORGANIC  LIFE. 


107 


MAN  KIND  in  its  physical  gradations,  in  the  geo- 
graphical distribution  of  its  simultaneously  ex- 
isting types,  in  the  influence  which  it  derives 
from  the  forces  of  nature,  and  on  the  contrary, 
though  in  a  less  degree,  the  influence  which  it 
has  exercised  on  these.  Dependent,  although 
not  to  the  same  extent  as  plants  and  animals, 
on  the  ground  and  the  meteorological  processes 
of  the  atmosphere,  more  readily  escaping  from 
under  the  dominion  of  some  of  the  natural  for- 
ces through  activity  of  mind,  and  intelligence 
exalted  by  degrees,  as  well  as  through  a  won- 
derful pliability  of  constitution,  which  adapts 
itself  to  every  climate,  the  human  kind  takes 
an  essential  part  in  the  whole  vitality  of  the 
earth.  Through  thesis  relations  we  are  brought 
into  contact  with  the  obscure  and  much  agita- 
ted problem  of  the  possibility  of  common  de- 
scent in  the  circle  of  ideas  which  the  physical 
cosmography  embraces.  The  investigation  of 
this  problem,  if  I  may  so  express  myself,  shall, 
through  ennobled  and  purely  human  interests, 
be  made  the  last  aim  of  my  work.  The  im- 
measurable realm  of  language,  in  the  diverse 
organizations  of  which,  the  capacities  of  na- 
tions are  foreshadowed,  as  it  were,  is  most  in- 
timately connected  with  the  subject  of  alli- 
ance of  race ;  and  what  even  slight  diversity 
of  race  is  competent  to  produce,  is  taught  us 
by  the  Hellenic  world  in  the  bloom  of  its  men- 
tal culture.  The  most  important  questions  in 
the  history  of  the  progress  of  society  connect 
themselves  with  ideas  of  descent,  community 
of  language,  and  immutability  in  an  original  di- 
rection of  the  affective  and  intellectual  nature 
of  man. 

So  long  as  extremes  in  diversity  of  colour 
and  configuration  were  alone  considered,  and 
the  first  liveliness  of  sensible  impression  was 
yielded  to,  there  might  have  been  the  disposi- 
tion to  consider  races,  not  as  mere  varieties, 
but  as  originally  different  kinds  of  men.  The 
permanency  of  certain  types(*''3)  even  amidst 
the  most  inimical  operation  of  external,  partic- 
ularly climatic  influences,  appeared  to  favour 
such  an  assumption,  short  though  the  time  be 
through  which  historical  information  has  come 
down  to  us.  But  vouching  far  more  strongly, 
according  to  my  views,  for  the  unity  of  the  hu- 
man race,  are  the  many  middle  tintsC*"*)  in  col- 
our of  skin,  and  grades  in  form  of  skull,  which 
the  rapid  spread  of  geographical  knowledge  in 
recent  times  has  made  known  to  us  ;  the  anal- 
ogy of  variety  in  other  wild  and  domesticated 
classes  of  animals,  and  the  sure  experience 
which  has  been  collected  in  regard  to  the  lim- 
its of  fruitful  hybrids  of  different  kinds("5). 
The  greater  number  of  the  contrasts  which  in 
former  times  were  believed  to  have  been  dis- 
covered, have  been  disposed  of  by  the  industri- 
ous work  of  Tiedemann,  "  On  the  Brain  of  the 
Negro  and  the  European,"  and  by  the  anatom- 
ical inquiries  of  Vrolik  and  of  Weber,  "  On  the 
Form  of  the  Pelvis."  If  we  embrace  the  dark- 
skinned  African  nations,  on  which  Prichard's 
admirable  work*  has  thrown  so  much  light,  in 
their  universality,  and  compare  them  with  the 
races  of  the  South  Indian  and  West  Australian 
Archipelagos,  with  the  Papuas  and  Alfourous 

*  [Researches  into  the  Physical  History  of  Mankind,  3d 
and  4th  edit.,  4  vols,  8vo,  1841-44.  The  Natural  History 
of  Man,  1  vol.  8vo,  1843,  2d  edit.,  1845.— Tr. J 


(Haraforans,  Endamenans),  we  see  clearly  that 
black  colour  of  the  skin,  woolly  hair,  and  negro- 
like features  are  by  no  means  always  conjoin- 
ed(*°*).  So  long  as  but  a  small  portion  of  the 
world  was  open  to  the  western  nations,  they 
necessarily  came  to  narrow  or  one-sided  con- 
clusions. Heat  of  sun  in  the  tropical  world, 
and  dark  colour  of  skin,  seemed  inseparable. 
"The  .Ethiopians,"  sings  the  old  tragedian^ 
Theodectes  of  PhaselisC*"^),  "  are  dyed  by  the 
near  sun-god  in  his  course,  with  a  dark  and 
sooty  lustre  ;  the  sun's  heat  crisps  and  dries  up 
their  hair."  The  expeditions  of  Alexander, 
which  were  so  influential  in  exciting  ideas  of 
the  physical  cosmography,  first  fanned  the  dis- 
pute on  the  uncertain  influence  of  climate  upon 
races  of  men. 

"  The  races  of  animals  and  plants,"  says  one 
of  the  greatest  anatomists  of  the  age,  Joannes 
Miiller,  in  his  very  comprehensive  "  Physiolo- 
gy of  Man,"*  *'  undergo  changes  during  their 
spread  over  the  surface  of  the  earth,  within  the 
limits  prescribed  to  species  and  genera.  But 
they  are  propagated  organically  as  types  of  va- 
rieties of  species.  From  the  co-operation  of 
different,  as  well  internal  as  external  condi- 
tions, not  to  be  specified  in  individual  instan^ 
ces,  have  the  present  races  of  animals  proceed- 
ed, the  most  remarkable  varieties  of  which  are 
met  with  amongst  those  that  are  capable  of  the 
widest  distribution  over  the  face  of  the  earth. 
All  the  races  of  men  are  forms  of  a  single  spe- 
cies, which  are  capable  of  fruitful  union  and  of 
propagation  ;  they  are  not  different  species  of 
one  genus  ;  were  they  so,  their  mixed  progeny 
would  prove  unfruitful.  Whether  the  various 
races  of  men  are  descended  from  several  or 
from  a  single  primitive  man,  cannot  be  decided 
from  experience"(*'"*). 

Geographical  Researches  into  the  ancient 
seat,  the  cradle,  as  it  has  been  called,  of  the 
human  race,  possess  in  fact  a  purely  mythical 
character.  "  We  know,"  says  William  von 
Humboldt,  in  a  work  yet  unpublished,  on  the 
Diversity  of  Languages  and  of  Nations,  "  we 
know,  neither  historically,  nor  by  tradition  that 
can  be  trusted,  of  any  epoch  in  which  the  hu- 
man race  have  not  been  collected  together  into 
tribes  or  communities.  Whether  this  condi- 
tion was  the  original  one,  or  first  arose  at  a  la- 
ter period,  cannot  be  decided  historically.  Iso- 
lated traditions  met  with  in  many  different  pla- 
ces on  the  earth's  surface  negative  the  first  as- 
sumption, and  derive  the  whole  of  the  human 
race  from  a  single  human  pair.  The  wide  dif- 
fusion of  this  belief  has  sometimes  led  to  its 
being  assumed  as  a  primitive  recollection 
among  mankind.  But  this  very  circumstance 
much  rather  informs  us,  that  nothing  tradition- 
al, and  nothing  historical  lies  at  the  root  of  the 
persuasion,  but  merely  similarity  of  the  human 
faculty  of  conception  which  leads  to  the  same 
explanation  of  the  same  phenomenon ;  many 
similar  myths  have  very  certainly  arisen,  with- 
out historical  connection,  out  of  the  similarity 
of  man's  poetical  and  speculative  constitution. 
These  traditions  also  bear  the  entire  stamp  of 
human  invention  in  this,  that  they  explain  the 
phenomenon  of  the  first  appearance  of  the  hu- 


*  [Ably  rendered  into  English,  and  copiously  commented 
and  illustrated,  by  Dr.  Wm.  Baly,2  vols.  8vo,  Load.,  1843. 
— Tb.] 


1108 


ORGANIC  LIFE. 


man  race  (a  point  which  lies  beyond  the  reach 
of  all  experience),  in  a  way  that  accords  with 
the  experience  of  the  day,  and  proceed  to  show 
how,  in  times  when  the  human  kind  must  al- 
ready have  existed  for  thousands  of  years,  a 
desert  island,  or  a  sequestered  valley,  may 
have  been  peopled.  It  is  in  vain,  however, 
that  reflection  attempts  to  dive  into  this  prob- 
lem of  original  production,  seeing  that  man  is 
so  bound  up  with  his  kind  and  with  time,  that 
an  individual  without  contemporaries,  and  with- 
out a  past,  can  by  no  means  be  conceived  in 
human  existence.  Whether,  therefore,  in  this 
question,  which  can  neither  be  decided  by  the 
way  of  reasoning  nor  of  experience,  this  pre- 
tended tradition  be  the  historical  truth,  or  the 
human  kind  from  its  commencement  has  pos- 
sessed the  earth  in  the  shape  of  tribes  or  com- 
munities, can  neither  be  determined  by  Philol- 
ogy out  of  the  elements  of  its  science,  nor,  as- 
suming the  decision  on  other  grounds,  can  it 
use  the  conclusion  come  to  in  illustration  of  its 
own  propositions." 

The  distribution  of  the  human  kind  is  no 
more  than  a  distribution  into  varieties,  which 
have  been  designated  by  the  somewhat  indefi- 
nite word  races.  As  in  the  vegetable  kingdom, 
and  in  the  natural  history  of  birds  and  fishes, 
the  system  of  grouping  into  many  small  fami- 
lies is  more  certain  than  that  into  a  few  divis- 
ions, embracing  larger  masses,  so  does  it  ap- 
pear to  me  preferable,  in  the  determination  of 
races  of  men,  to  arrange  them  into  smaller  fam- 
ilies. The  old  classification  of  m'y  master,  Blu- 
menbach,  into  five  races — the  Caucasian,  the 
Mongolian,  the  American,  the  Ethiopian,  and 
the  Malayan,  may  be  followed  ;.  or  with  Prich- 
ard,  seven  Vaces  may  be  assumed — the  Trani'- 
an(*°''),  the  Turanian,  the  American,  the  Hot- 
tentot and  Buschman,  the  Negro,  the  Papuan, 
and  the  Alfoarousian  ;  still  is  there  no  typical 
rigour,  no  natural  principle  of  classification,  rec- 
ognizable in  such  arrangements.  The  extremes 
in  reference  to  configuration  and  colour  are  sep- 
arated, without  reference  to  the  stocks  that 
cannot  be  connected  with  one  or  other  of  these, 
and  which  have  at  one  time  been  entitled  Scyth- 
ian, at  another  Allophylian  races.  Tranian,  in 
reference  to  the  European  nations,  is  certainly 
a  less  objectionable  name  than  Caucasian ; 
but  it  may  be  maintained  in  a  general  way, 
that  geographical  designations  as  derivative 
points  of  races  are  very  indeterminate,  when 
the  country  which  is  chosen  to  confer  the  title 
on  the  race,  for  example,  Turan  (Maweran- 
nahr),  has  at  different  epochs  been  possessed 
by  most  dissimilar  races  —  of  Indo-Germanic 
and  Finnish,  but  not  Mongolian  origin("°). 

Languages,  as  mental  creations  of  man,  as 
closely  intertwined  with  his  spiritual  develop- 
ment, inasmuch  as  they  exhibit  national  forms, 
possess  high  importance  in  connection  with  the 
recognizable  similarities  and  dissimilarities  of 
races.  They  have  this  importance,  because 
community  of  descent  leads  into  the  myste- 
rious labyrinth  in  which  the  enchainment  of 
physical  (bodily)  aptitude  with  mental  power 
is  exhibited  in.  an  endless  variety  of  forms. 
The  brilliant  advances  which  philosophical  phi- 
lology has  made  in  Germany,  especially  within 
the  last  half  century,  facilitate  inquiries  into  the 
national  character  of  languages,  into  that  which 


descent  appears  to  have  added  to  them(*"). 
As  in  all  other  regions  of  abstract  speculation, 
however,  the  danger  of  being  deceived  is  here 
set  beside  the  hope  of  collecting  a  rich  and  as- 
sured booty. 

Positive  ethnographical  studies,  based  upon 
solid  historical  knowledge,  warn  us  that  the 
greatest  caution  is  necessary  in  all  compari- 
sons of  nations  A^ith  the  languages  which  they 
have  made  use  of  at  determinate  epochs.  Sub- 
jugation, living  long  together,  the  influence  of 
a  foreign  religion,  and  intermixture  of  races, 
though  often  effected  by  a  relatively  small 
number  of  more  powerful  and  more  civilized 
intruders,  have  produced  a  phenomenon  which 
has  recurred  in  like  measure,  in  both  conti- 
nents, viz.  :  that  totally  different  families  of 
languages  are  met  with  in  use  by  one  and  the 
same  race  ;  that  among  nations  of  very  differ- 
ent descent,  idioms  of  the  same  original  tongue 
are  encountered.  Asiatic  conquerors  have  had 
the  greatest  influence  upon  such  phenomena. 

Speech,  however,  is  a  portion  of  the  natural 
science  of  mind  ;  and  if  the  freedom  wherewith 
the  spirit  in  a  state  of  happy  independence 
steadily  pursues  the  self-elected  course  under 
totally  different  physical  influences,  strives 
vigorously  to  withdraw  it  from  the  power  of 
the  earth,  still  the  unfettering  is  never  quite 
complete.  There  ever  remains  something  of 
that  which  belongs  to  natural  aptitude,  to  de- 
scent, to  climate,  to  the  bright  blue  sky,  or  to 
the  cloudy  atmosphere  of  the  insular  world. 
And  since  copiousness  and  grace  in  the  struc- 
ture of  a  language  are  unfolded  from  thought 
as  from  the  most  delicate  blossom  of  the  soul, 
so  would  we  not,  that  in  the  intimacy  of  the 
bond  which  unites  the  two  spheres — that  of  the 
physical  nature,  and  that  of  the  intellect  and 
•feelings — our  delineation  should  be  without  the 
favourable  light  and  colouring  which  it  must 
derive  from  a  consideration,  here  only  indica- 
ted, it  is  true,  of  the  relations  of  hereditary  de- 
scent to  language. 

In  maintaining  the  unity  of  the  human  kind, 
we  at  the  same  time  repudiate  all  the  unsatis- 
factory assumptions  of  higher  and  lower  races 
of  men(*^=').  There  are  races  of  men  more 
flexible,  more  highly  polished,  through  mental 
culture  more  ennobled,  but  none  naturally  more 
noble.  All  are  in  equal  measure  ordained  for 
liberty ;  for  liberty  which  in  ruder  conditions 
of  society  appertains  to  the  individual,  which 
in  more  polished  states,  in  civil  life  and  among 
men  in  the  enjoyment  of  political  institutions, 
is  the  right  of  the  community.  "  If  we  would 
signalize  an  idea  which  is  conspicuous  through- 
out the  entire  current  of  history,  and  ever  with 
a  wider  import,  when  any  one  assures  us  of 
the  much-discussed,  but  still  more  extensively 
misapprehended  perfectibility  of  mankind,  it  is 
the  idea  of  Humanity  :  the  effort  to  cast  down 
the  barriers  which  prejudice  and  one-sided 
views  of  every  kind  have  hostilely  raised  be- 
twixt man  and  man,  and  to  treat  mankind  at 
large,  without  reference  to  religion,  to  nation, 
or  to  colour,  as  one  great  and  nearly-related 
family — as  a  whole,  that  exists  for  the  accom- 
plishment of  this  single  end,  the  free  devel- 
opment   OF    INTERNAL   POWER.      This  is  thO  OX- 

treme,  the  ultimate  purpose  of  the  social  state, 
and  at  the  same  time  it  is  the  tendency  infixed 


ORGANIC  LIFE. 


109 


in  the  nature  of  man  striving  after  indefinite 
extension  of  his  being.  He  looks  upon  the 
ground,  as  it  spreads  out  beneath  his  feet — on 
the  heavens,  as  they  arch  over  his  head — on 
the  stars  that  shed  their  light  upon  him,  as  in- 
timately his  own,  as  given  to  him  for  contem- 
plation and  for  reality.  The  very  child  longs 
to  get  beyond  the  hills,  the  lakes  that  bound 
his  narrow  home  ;  and  then,  plant-like,  he  longs 
to  returri ;  for  it  is  a  touching  and  a  beautiful 
element  in  the  nature  of  man,  that  all  his  de- 
sires for  things  agreeable  and  for  things  lost, 
still  approve  him  exclusively  attached  to  the 
moment :  firmly  rooted  in  the  inmost  nature  of 
man,  and  at  the  same  time  commanded  by  his 
loftiest  aspirations,  this  benevolent,  this  hu- 
mane association  of  the  entire  race  becomes 
one  of  the  grand  leading  ideas  in  the  history  of 
mankind"(*^^). 

With  these  words,  which  draw  their  charm 
from  the  depth  of  the  feelings  that  gave  them 


birth,  be  it  allowed  the  Brother  to  conclude 
this  general  representation  of  the  natural  phe- 
nomena of  the  universe.  From  the  farthest 
nebulae  of  heaven,  and  from  revolving  double 
stars,  we  have  come  down  to  the  smallest  or- 
ganisms of  the  animal  creation  that  live  by  sea 
and  land,  and  to  the  delicate  vegetable  germs 
that  cover  the  rocks  on  the  flanks  of  snow-clad 
mountain  summits.  Here  we  have  found  that 
the  phenomena  could  be  arranged  according  to 
laws  which  are  partially  known.  Laws  of  an- 
other and  a  mysterious  kind  come  into  play  in 
the  higher  circles  of  life  in  the  organic  world  ; 
in  those  especially  that  are  occupied  by  the  ra- 
ces of  mankind  variously  conformed,  endowed 
with  creative  mental  energies,  and  gifted  with 
the  faculty  of  inventing  language.  A  physical 
Delineation  of  Nature  indicates  the  boundary 
where  the  sphere  of  intelligence  begins,  and  the 
far-piercing  glance  is  lost  in  another  world.  It 
indicates,  but  does  not  pass  the  boundary. 


<&( 


NOTES  TO  PRECEDING  SECTION. 


1  (p.  29.) — The  optical  considerations  on  the  differences 
which  a  single  luminous  point  or  a  disc  of  measurable  an- 
gle presents,  in  which  the  power  of  light  remains  the  same 
at  every  distance,  maybe  found  discussed  by  Arago,  Analyse 
des  travaux  de  Sir  William  Herschel  (Annuaire  du  Bu- 
reau des  Long.  1842,  p.  410-412.  and  441.) 

2  (p.  29.) — "  The  two  Magellanic  clouds,  Nubecula  ma- 
jor and  minor,  are  highly  remarkable  objects.  The  larger 
cloud  is  an  aggregation  of  stars,  and  consists  of  clusters  of 
■tars  of  irregular  configuration,  of  globular  clusters  and 
nebulous  stars  of  different  sizes  and  densities.  Between 
these  lie  large  nebulie  which  are  not  resolvable  into  stars, 
which  apparently  are  star  dust,  and  even  with  the  20-feet 
telescope  present  themselves  only  as  a  general  luminous- 
ness  of  the  field,  as  a  brilliant  back-ground,  upon  which 
other  objects  of  very  remarkable  and  incomprehensible  con- 
figuration are  scattered.  In  no  other  part  of  the  heavens 
are  so  many  clusters  of  nebulse  and  of  stars  collected  to- 
gether within  so  small  a  compass  as  in  this  cloud.  The 
Nubecula  minor  is  much  less  beautiful;  it  shows  a  larger 
quantity  of  unresolvable  nebular  light,  and  the  groups  of 
stars  it  includes  are  fewer  in  number  and  smaller." — Letter 
from  Sir  John  Herschel,  dated  Feldhuysen,  Cape  of  Good 
Hope,  June  13.  1836. 

3  (p.  29.)  —  The  fine  expression,  xrf/Jroj  ovpavou,  which 
Hesychius  borrows  from  an  unknown  poet,  I  have  rendered 
as  above  by  the  phrase  "garden  of  heaven  ;"  xoRroi  may, 
perhaps,  rather  signify  an  enclosed  place,  and  would  then 
be  better  translated,  the  celestial  space.  The  connection 
of  the  word  with  the  German  garten,  English  garden,  (Goth- 
ic gards,  according  to  Jacob  Grimm,  from  gairdan,  cingere, 
to  gird,)  is,  however,  not  to  be  overlooked,  any  more  than 
the  affinity  with  the  Sclavonian  grad,  gorod,  and,  as  re- 
marked by  Pott  (Etymol.  Forsch.  Th.  i.  S.  144),  with  the 
Latin  chors,  (whence  the  modern  words  corte,  court,  cours), 
and  the  Ossetic  khart.  The  northern  gard,  gard,  a  fence, 
an  enclosure,  and  a  country-seat ;  and  the  Persian  gerd, 
gird,  a  circle,  and  also  a  princely  country-seat,  a  castle,  a 
town  ;  as  in  the  old  names  in  Firdusi's  Schahnameh :  Siya- 
wakschgird,  Daral)gird,  &c. 

4  (p.  30.)— For  u  Centauri,  vide  Maclear,  in  Trans.  As- 
tronom.  Soc.,  vol.  xii.  p.  370.  More  probable  mean  error 
0"0640:  for  61  Cygni,  vide  Bessel,  in  Schum.  Jahrbuch, 
1839,  S.  47—49,  and  in  Schum.  Astronom.  Nachr.  Bd.  17, 
S.  401,  402  Mean  error  0"0I41.  On  the  relative  distan- 
ces of  stars  of  different  orders,  as  those  of  the  third  magni- 
tude are  probably  three  times  more  distant,  and  as  to  how 
we  are  to  imagine  the  strata  of  stars  in  their  bodily  config- 
uration, 1  find  in  Kepler's  Epitome  Astronomiae  Copernica- 
nae,  1618,  tom.  i.  lib.  i.  p,  34—39,  a  remarkable  passage: 
"  Sol  hie  noster  nil  aliud  est  quam  una  ex  fixis,  nobis  major 
et  clarior  visa,  quia  proprior  quam  fixa.  Pone  terram  stare 
ad  latus,  una  semidiametro  viae  lacteae,  tunc  haec  via  lac- 
tea  apparebit  circulus  parvus,  vel  ellipsis  parva,  tota  decli- 
nans  ad  latus  alterum  ;  eritque  simul  uno  intuitu  conspicua, 
qua  nunc  non  potest  nisi  dimidia  conspici  quovis  momento. 
Itaque  fixarum  sphaera  non  tantum  orbe  stellarum,  sed  etiam 
circulo  lactis  versus  nos  deorsum  est  terminata." 

»  (p.  31.) — "  Si  dans  les  zones  abandonn6es  par  I'atmo- 
sph^re  du  soleil  il  s'est  trouv6  des  molecules  trop  volatiies 
pour  s'unir  entre  elles  ou  aux  planetes  ;  elles  doivent  en 
continuant  de  circuler  autour  de  cet  astre  offrir  toutes  les 
apparences  de  la  lumiere  zodiacale,  sans  opposer  de  resis- 
tance sensible  aux  divers  corps  du  systeme  plan6taire,  soit 
&  cause  de  leur  extreme  raret6^  soit  parce  que  leur  mouve- 
ment  est  a  fort  peu  pres  le  mfime  que  celui  des  planetes 
qu'elles  rencontrent."— Laplace,  Exp.  du  Syst.  du  Monde, 
(5e  ed.)  p.  415. 

6  (p.  31.)— Laplace,  loc.  cit.  p.  396  and  414. 

7  (p.  31.)  — Littrow,  Astronomic,  1825,  Bd.  ii.  S.  107. 
Madler,  Astr.  1841,  S.  212.     (Laplace,  loc.  cit.  p.  210.) 

8  (p.  31.)— Kepler  on  the  decreasing  density  and  increas- 
ing volume  of  the  planets,  with  their  distance  from  the  sun, 
which  IS  described  as  the  most  dense  of  all  bodies  ;  vide  his 
Epitome  Astron.  Copern.  in  vii.  libros  digesta,  1618 — 1622 
p.  420.  Leibnitz  was  also  of  Kepler's  and  Otto  von  Gue- 
ricke's  opinion,  that  the  planets  increase  in  volume  in  pro- 
portion to  their  distance  from  the  sun.  Vide  his  Brief  an 
den  Magdeburger  Burgermeister  (Mainz,  1671),  in  Leibnitz, 
deutschen  Schriften,  herausg.  von  Guhrauer,  Th.  i.  S.  264. 

9  (p.  31.)— For  a  co  ordination  of  the  masses,  see  Encke, 
in  Schum.  Astr.  Nachr.  1843,  Nr.  488,  S.  114. 


t.^V,t^f:l7l}^  ??  sehiidiameter  of  the  moon,  according 
to  Burckhardt's  determination,  be  02725,  and  Its  volumi 
T»o  9'  ''*  density  would  then  come  out  0-5596  •  nearly  l- 
^^'^  M^ll^-  ^^"  S"^  ?•  ^^'Jler,  der  Mond,  S.  1  und  10. 
wie  Madler,  Astr.  S.  157.  The  actual  contents  of  the  moon, 
acording  to  Hansen,  equal  -g\,  according  to  Madler,  ^.^ 
of  the  material  contents  of  the  earth  ;  its  mass  j-»^  that 
of  the  earth.  In  the  case  of  the  largest  of  airjuniter's 
satellites,  the  third,  the  relations  to  the  primary  in  volume 
f '■''  rswro  ;  'n  tlie  mass,  yy^.  On  the  oblateness  of 
Uranus,  vide  Schum.  Astron.  Nachr.  1844,  Nr.  493 

11  (p.  33.)— Beer  und  Madler,  1.  c.  ^  185,  S.  208,  u.  (f  347 
S.  332 ;  also  their  Phys.  Kenntniss  der  himml.  Korner.  S* 
4  und  69,  Tab.  i.  ' 

12  (p.  34.)— The  four  oldest  comets  whose  orbits  hava 
been  calculated  —  and  this  from  Chinese  observaMons— are 
those  of  the  years  24  (under  Gordiau  111.),  539  (under  Jus- 
tinian), 565  and  837.  Whilst  the  last  of  these  comets  was 
less  than  500,000  miles  from  the  earth,  and  Louis  the  Pious, 
greatly  alarmed,  was  seeking  to  avert  the  presumed  danger 
by  founding  various  monasteries,  the  Chinese  astronomers 
were  following  quite  scientifically  the  course  of  the  star, 
whose  tail,  60°  in  length,  appeared  first  simple  and  then 
divided.  The  first  comet  which  could  be  calculated  from 
European  observations  alone,  is  that  of  1456,  (those  of  Hal- 
ley,  which  were  long  but  incorrectly  regarded  as  the  first 
accurate  elements).  Vide  Arago,  in  Annuaire,  1836,  p  204 
See,  also,  under  Note  26. 

13  (p.  34.)— Arago,  in  Annuaire,  1832,  p.  209—211.  In 
the  same  way  as  the  tail  of  the  comet  of  J402  was  seen  in 
bright  sunshine,  so  was  the  last  great  comet  of  1843  seen 
both  in  Its  nucleus  and  tail  between  1  and  3  o'clock  on  the 
28th  of  February  by  J.  G.  Clarke,  of  Portland,  Maine,  U.  S. 
Distances  of  the  extremely  dense  nucleus  from  the  sun's 
edge  could  be  measured  with  great  accuracy.  The  nucleus 
and  tail  presented  themselves  as  a  very  pure  white  cloud  ; 
only  between  the  tail  and  the  nucleus  there  was  a  darker 
space. — American  .Journal  of  Science,  vol.  xlv.  No.  l,p  229 
(Schum.  Astr.  Nachr.  1843,  Nr.  491,  S.  175.) 

1-*  (p.  34.)  -Phil.  Trans,  for  1808,  pt.  ii.  p.  155,  and  for 
1812,  pt.  I.  p.  1J8.  The  diameters  of  the  nuclei  found  by 
Herschel  were  538  and  428  English  miles.  For  the  dimen- 
sions of  the  comets  of  1798  and  1085,  vide  Arago,  in  An- 
nuaire pour  1832,  p.  203. 

15  (p.  35.)— Arago  des  changemens  physiques  de  la  Co- 
mete  de  Halley  du  15—23  Oct.  1835,  in  Ann.  1836,  p.  218— 
221.  The  more  usual  direction  of  the  tail  or  emanation 
was  observed  in  Nero's  time  :  "  Comae  radios  solis  effu- 
giunt."     Seneca,  Nat.  Quaest.  vii.  20. 

lt>  (p.  35.)— Bessel,  in  Schum.  Astr.  Nachr.  1836,  Nr. 
300-302,  S.  188,  192,  197,  200,  202,  und  230.  Also  in 
Schum.  Jahrb.  1837,  S.  149—168.  W.  Herschel  also  be- 
lieved  that  he  had  observed  the  rotation  of  the  nucleus  and 
tail  lu  his  observations  on  the  beautiful  comet  of  1811 
(Philos.  Trans.  1812,  pt.  i.  p.  140.)  So,  also,  Dunlop  in  the 
third  comet  of  1825  at  Paramatta. 

17  (p.  35.) -Bessel,  in  Astr.  N.lchr.  1836,  Nr.  302,  S.  231, 
(Schum.  Jahrb.  1837,  S.  175).  Vide,  also.  Lehmann  uber 
Cometenschweife  in  Bode*s  Astron.  Jahrb.  fur  1826,  S.  168. 

18  (p.  35.)— Aristot.  Meteor,  i.  8,  11—14  und  19—21  (ed* 
Ideler  t.  i.  p.  32—34).  Biese,  Phil,  des  Aristoteles,  Bd.  ii. 
S.  86.  In  the  influence  which  Aristotle  exerted  on  the 
whole  of  the  middle  ages,  it  is  infinitely  to  be  lamented  that 
he  showed  himself  so  inimically  disposed  to  the  grand  views 
of  the  structure  of  the  universe  espoused  by  the  old  Pytha- 
goreans, and  which  approached  the  truth  so  closely.  He  de- 
clares the  comets  to  be  transient  meteors  belonging  to  our 
atmosphere,  in  the  same  book  in  which  he  quotes  the  opin- 
ion of  the  Pythagoreans  to  the  effect  that  comets  were 
planets  with  long  periods  of  revolution.  This  doctrine  of 
the  Pythagoreans,  which,  however,  from  the  testimony  of 
Apollonins  Myndius,  appears  to  be  much  older,  and  to  have 
been  that  of  the  Chaldeans,  passed  over  to  the  imitative  . 
Romans.  The  Myndian  describes  the  orbits  of  comets  aa 
passing  far  into  the  upper  celestial  spaces.  Whence  Seneca 
(Nat.  Quaest.  vii.  17) :  "  Cometes  non  est  species  falsa,  sed 
proprium  sidus  sicut  solis  et  lunae:  altiora  mundi  secat  et 
tunc  demum  apparet  quum  in  imum  cursum  sui  venit ;"  and 
(vii.  27):  "  Cometas  seternos  esse  et  sortis  ejusdem,' cuius 
cstera  (sidera),  etiamsi  faciem  illis  non  habent  similem.** 


112 


NOTES  TO  PRECEDING  SECTION. 


Pliny,  too,  evidently  plays  upon  Apollonius'  words,  when 
he  says,  "Sunt  qui  et  hsec  sidpra  pcrpetua  esse  credant 
suoque  ambitu  ire,  sed  non  nisi  relicta  a  sole  cerni." 

l^»  (p.  35.)— Olbers,  in  the  Astr.  Nachr.  1828,  S.  157,  184. 
Arago,  de  la  constitution  physique  des  cometes  im  Annuaire 
de  1832,  p.  203 — 208.  The  ancients  had  already  seen  it  as 
remarkable  that  we  can  see  through  comets  as  through  a 
flame.  The  oldest  testimony  to  stars  having  been  seen 
through  comets,  is  that  of  Democritus  (Aristot.  Meteorol. 
i.  6,  11).  This  statement  leads  Aristotle  to  the  not  unim- 
portant observation,  that  he  himself  had  seen  the  occulta- 
tion  of  one  of  the  stars  of  Gemini  by  Jupiter.  Seneca  very 
certainly  refers  to  the  trans! ucency  of  the  tail  only  (Nat. 
Quxst.  vii.  18)  :  "  Non  in  ea  parte  qua  sidus  ipsum  est 
spissi  et  solidi  ignis,  sed  qua  rarus  splendor  occurrit  et  in 
crines  dispergitur.  Per  intervalla  ignium,  non  per  ipsos" 
(vii.  26).  The  last  portion  of  the  remark  is  superfluous,  as 
we  do  positively  See  through  a  flame  if  it  be  not  too  thick, 
as  remarked  by  Galileo  (Lettera  a  Mons.  Cesarini,  1619). 

20  (p.  35.)— Bessel  in  den  Astr.  Nachr.  1836,  Nr.  301,  S. 
204 — 206.  Struve  im  Rocneil  des  Mem.  de  I'Acad.  de  St. 
Pet.  1836,  p.  140-143,  and  Astr.  Nachr.  1836,  Nr.  303. 
"  For  Dorpat,  the  star  during  the  conjunction,  was  only 
2"'2  from  the  brightest  point  of  the  comet.  The  star  re- 
mained steadily  visible,  and  was  not  sensibly  weakened  ; 
whilst  the  nucleus  of  the  comet  appeared  to  be  extinguished 
beside  the  brilliancy  of  the  minute  star  (9th  to  the  10th 
magnitude)." 

21  (p,  35.) — The  first  attempts  of  Arago  to  apply  polariza- 
tion to  Comets  were  made  on  the  3d  July,  1819,  the  evening 
of  the  sudden  appearance  of  the  great  comet.  I  was  present 
in  the  observatory,  and  along  with  M.  Mathieu  and  the  late 
M.  Bouvard,  was  satisfied  of  the  inequality  of  the  strength 
of  light  in  the  polariscope  when  it  received  the  light  of  the 
comet.  With  Capella,  which  was  near  the  comet,  and 
about  the  same  altitude,  the  images  were  of  like  intensity. 
When  Halley's  comet  appeared  in  1835,  the  apparatus  was 
so  altered  that  it  gave  two  images  of  complementary  col- 
ours— green  and  red,  according  to  the  discovery  by  Arago 
of  chromatic  polarization.  Armales  de  Chimie",  t.  xiii.  p. 
108.  Annuaire,  1832,  p.  216.  "  On  doit  conclure,"  says 
Arago,  "de  I'ensemble  de  ces  observations  que  la  lumiere 
de  la  comete  n'etait  pas  en  totalite  compos6e  de  rayons 
doues  des  propriei6s  de  la  lumiere  directe,  propre  ou  assim- 
ilee  :  il  s'y  trouvait  de  la  lumiere  reflechie  sp^culairement 
ou  polarisee,  c'est-A-dire  venant  du  soleil.  On  ne  peut  as- 
surer d'une  maniere  absolue  que  les  cometes  brillent  seule- 
ment  d'un  eclat  d'ernprunt.  En  eflTet  en  devenant  lumineux, 
par  eux-m^mes,  les  corps  ne  perdent  pas  i)our  cela  la  faculte 
de  r6flechir  des  lumieres  etrangeres." 

3i  (p.  36.)— Arago,  in  Ann.  1832,  p.  217—220.  Sir  John 
Herschel,  Astron.  ^  488. 

23  (p.  36.)— Encke,  in  the  Ast.  Nachr.  1843,  Nr.  489,  S. 
130—132. 

24  (p.  36.)— Laplace,  Exp.  du  Syst.  du  Monde,  p.  216  and 
237. 

25  (p,  36.)— Littrow,  Beschreibende  Astr.  1835,  S.  274. 
On  the  inner  comet  lately  discovered  by  M.  Faya,  of  the 
Parisian  Observatory,  whose  excentricity  is  0  551,  perihe- 
liac  distance  1  690,  and  apheliac  distance  5-832,  Schuni. 
Astr.  Nachr.  1844,  Nr.  495. 

26  (p.  37  ) — Laugier,  dans  les  Comptes,  rendus  des  Stan- 
ces de  I'Acad.  1843,  t.  xvi.  p.  1006. 

27  (p.  37.) — Fries,  Vorlesungen  iiber  die  Stemkunde  1833, 
S.  262—  267.  A  not  very  fortunate  argument  for  the  benefi- 
cent nature  of  comets  occurs  in  Seneca,  who  speaks  (Nat. 
Qusest.  vii.  17  and  21)  of  the  comet,  "  Quem  nos  Neronis 
principatu  laetissimo  vidimus  et  qui  cometis  detraxit  infami- 
am." 

28  (p.  38.) — One  of  my  friends,  accustomed  to  trigonomet- 
rical surveys,  saw  his  chamber  illuminated  by  a  fire-ball  at 
mid-day,  and  while  the  sun  was  shining,  in  the  town  of  Po- 
payan  (N.  lat.  2°  26' ;  5520  feet  above  the  sea  level).  He 
was  standing  with  his  back  to  the  window,  and  when  he 
turned  round  a  great  portion  of  the  course  traversed  by  the 
ball  was  still  most  brilliantly  lighted.  The  titles  for  falling- 
stars  are  often  extremely  "vulgar :  the  Germans  speak  of 
them  as  star-snuffs :  according  to  the  vulgar  idea  the  lights 
of  heaven  want  snuffing.  In  the  woody  country  of  the  Ori- 
noco, and  on  the  solitary  banks  of  the  Cassiquiare,  the  shoot- 
ing stars  were  designated  by  the  natives  star-urine,  and  the 
dew  which  lay  on  the  beautiful  leaves  of  the  Heliconias  hke 
pearls,  was  star-spittle.  The  Lithuanian  Mythus  gives  a 
more  noble  and  imaginative  interpretation  of  the  nature  and 
significance  of  falling  stars  ;  "  The  spinstress  Werpeja  be- 
gins to  spin  the  thread  of  the  destiny  of  the  new-born  child, 
and  each  of  these  threads  ends  in  a  star.  And  then  when 
death  approaches  the  man,  the  thread  breaks  and  the  star 
falls,  quenching  its  light,  to  the  earth."— Jacob  Grimm, 
deutsche  Mythologie,  1843,  S.  685. 

29  (p.  38.)— From  the  account  of  Denison  Olmsted,  Profes- 
sor of  Yale  College,  New  Haven,  Connecticut,  IJ.  S.,  vide 
Poggendorif's  Annaleu  der  Physik,  Bd.  xxx.  S.  194.  Kep- 
ler, who  banishes  falling  stars  from  astronomy,  they  being, 


according  to  him,  mere  meteors,  engendered  by  emanatioM 
from  the  earth,  still  expresses  himself  very  cautiously  m 
regard  to  them.  "  Stellaj  cadenles,"  says  he,  "  sunt  materia 
viscida  inflammata.  Earum  aliquae  inter  cadendum  absu- 
muntur,  aliqu*  vere  in  terram  cadunt,  pondere  suo  tractaj. 
Nee  est  dissimile  vero,  quasdam  conglobatas  esse  ex  mate- 
ria foBCulentA,  in  ipsam  auram  ffitheream  immixta:  exque 
aetheris  regione,  tractu  rectilineo,  per  aerem  trajicere,  ceu 
minutes  cometas,  occultA  causa  motua  utrorumque." — Kep- 
ler, Epit.  Astron.  Copernicanae,  t.  i.  p.  80. 

30  (p.  38.)— Relation  historique,  t.  i.  p.  80,  213,  and  527. 
If  we  distinguish  a  head  or  nucleus  and  a  tail  in  falling  stais 
as  in  comets,  we  are  made  aware  of  the  greater  transparency 
of  the  atmosphere  iix  tropical  regions  by  the  greater  length 
and  brilliancy  of  their  trains.  The  phenomenon  need  not 
therefore  be  more  frequent  because  it  is  more  readily  seen, 
and  remains  longer  visible.  The  influence  of  the  state  ol 
the  atmosphere  also  shows  itself  occasionally  in  connection 
with  falling  stars  even  in  our  temperate  zone,  and  at  very 
short  distances.  Wartmanu  informs  us,  that  on  occasion 
of  one  of  the  November  phenomena,  the  difference  between 
the  number  of  meteors  seen  at  Geneva,  and  at  Planchettes, 
two  places  very  near  to  one  another,  was  1  :  7  (Mfem.  sur  les 
Etoiles  filantes,  p.  17).  The  train  of  the  falling  star,  upon 
which  Brandes  has  made  so  many  accurate  and  delicate  ob- 
servations, is  by  no  means  to  be  ascribed  to  the  continuance 
of  the  impression  of  light  upon  the  retina.  It  sometimes 
continues  visible  for  a  whole  minute  ;  in  rare  cases  even 
longer  than  the  light  of  the  head  of  the  falling  star.  The 
luminous  track  then  usually  remains  motionless  (Gilb.  Ann. 
Bd.  xiv.  S.  251).  This  circumstance  also  proclaims  the 
analogy  between  large  shooting  stars  and  fire-balls.  Admi- 
ral Krusenstern,  in  his  voyage  round  the  world,  saw  the 
tail  of  a  fire-ball  that  had  long  vanished,  remain  visible  for 
an  hour,  with  very  little  apparent  motion  (Reise,  Th.  i.  S. 
58).  Sir  Alexander  Burnes  gives  a  charming  account  of  the 
transparency  of  the  dry  atmosphere  of  Bokhara  (N.  lat.  39^ 
43',  1200  feet  above  the  sea-level),  so  favourable  formerly 
to  the  study  of  astronomy  :  "  There  is  a  constant  serenity 
in  its  atmosphere,  and  an  admirable  clearness  in  the  sky. 
At  night,  the  stars  have  uncommon  lusire,  and  the  milky- 
way  shines  gloriously  in  the  firmament.  There  is  also  a 
never-ceasing  display  of  the  most  brilliant  meteors,  which 
dart  like  rockets  in  the  sky  ;  ten  or  twelve  of  them  are 
sometimes  seen  in  an  hour,  assuming  every  colour;  fiery, 
red,  blue,  pale  and  faint.  It  is  a  noble  country  for  astro- 
nomical science,  and  great  must  have  been  the  advantage 
enjoyed  by  the  famed  observatory  of  Samarkand."  Burnes' 
Travels  into  Bokhara,  vol.  ii.  (1834)  p.  158.  We  must  not 
charge  ic  upon  the  solitary  traveller  that  he  speaks  of  ten 
or  twelve  falling  stars  in  an  hour  as  many ;  it  has  but  lately 
been  discovered,  from  careful  observation,  that  eight  meteors 
per  hour  are  the  mean  number  that  fall  within  the  circle  of 
vision  of  an  individual  (vide  Quelelet,  Correspond.  Mathem. 
Nov.  1837,  p.  447.)  Olbers,  the  acute  observer,  reduces 
this  number  to  from  five  to  six.  (Schum.  Jahrb.  1838,  S. 
325.) 

31  (p.  38.) — On  meteoric  dust,  vide  Arago,  in  Annuaire 
pour  1832,  p.  254.  I  have  very  lately  in  another  place  ( Asie 
centrale,  t.  i.  p.  408)  endeavoured  to  show  how  the  Scythian 
myth  of  the  sacred  gold  that  fell  glowing  from  heaven,  and 
remained  the  property  of  the  golden  hordes  of  Paralatae 
(Herod,  iv.  5 — 7),  may  have  been  the  obscure  recollection 
of  the  fall  of  an  Aerolite.  The  ancients  also  had  their  fa- 
bles (Dio  Cassius,  Ixxv.  12.')9)  strangely  enough  of  silver  that 
fell  from  heaven,  and  with  which  attempts  were  made  to 
plate  the  copper  money  under  the  Emperor  Severus.  Me- 
tallic iron  was  nevertheless  recognized  in  meteoric  stones 
by  Pliny  (ii.  56).  The  frequently  recurring  phrase  lapidi- 
bus  pluit,  must  not  be  always  viewed  as  referring  to  aero- 
lites. In  Livy  (xxv.  7)  it  is  used  in  connection  with  the  re- 
jected masses — pumice,  rapilli,  of  the  not  quite  extinct  vol- 
canic Mons  Albanus,  Monte  Cavo :  vide  Heyne,  Opusc. 
Acad.  t.  iii.  p.  261,  and  my  own  Relation  historique,  t.  i.  p. 
394.  To  another  circle  of  ideas  belongs  the  conflict  of  Her- 
cules against  the  Ligyes,  on  the  way  from  Caucasus  to  the 
Hesperides.  It  is  an  attempt  mythically  to  explain  the  ori- 
gin of  the  rounded  quartz  blocks  in  the  Ligyan  stone  field 
at  the  mouth  of  the  Rhone,  which  Aristotle  ascribes  to  aa 
earthquake,  Posidonius  to  the  action  of  the  waves  of  an  in- 
land sea.  But  in  the  fragments  of  the  Prometheus  Unbound 
of  .^schylus,  all  goes  forward  as  in  a  fall  of  Aerolites :  Ju- 
piter draws  together  a  cloud,  and  "  covers  the  land  with  a 
shower  of  rounded  stones  for  rain."  Posidonius  allows  him- 
self to  jest  at  the  geological  myth  of  the  fragments  and 
blocks.  The  Ligyan  stone  field  for  the  rest  is  faithfully  de- 
scribed by  the  ancients.  The  country  is  now  called  La 
Crau. — Guerin,  Mesures  barometriques  dans  les  Alpes  et 
M6t6orologie  d'Avignon,  1829,  ch.  xii.  p.  115. 

32  (p.  39.) — The  specific  gravity  of  Aerolites  varies  be- 
tween 1-9  (Alais)  and  4-3  (Tabor).  The  more  common  den- 
sity is  about  3,  water  being  assumed  as  1.  What  is  stated 
in  the  text  in  regard  to  the  actual  diameter  of  fire-balls,  is 
based  on  the  few  sfitisfactory  measurements  we  possess. 


NOTES  TO  PRECEDING  SECTION. 


113 


These  for  tlie  fire-ball  of  Weston  (Connecticut,  Dec.  14, 
1807)  assign  500,  for  the  one  observed  by  Le  Roi  (10th  July, 
1771)  about  1,000,  and  for  that  seen  by  Sir  Charles  Blagden 
{18th  Jan.  1783)  as  many  as  2,600  feet  in  diameter.  Brandes 
(Unterhaitung.  Ed.  i.  S.  42)  assig;ns  from  80  to  120  feet  to 
shooting  stars  ;  their  luminous  tails  being  from  3  to  4  miles 
in  length.  But  there  are  not  wanting  optical  grounds  for 
believing  that  the  apparent  diameter  of  fire-balls  and  shoot- 
ing stars  is  greatly  over-estimated.  The  volume  of  fire- 
balls is  certainly  not  to  be  compared  with  the  volume  of 
Ceres  (even  supposing  this  planet  to  be  no  more  than  70 
English  miles  iu  diameter,  as  has  been  estimated)  :  see  the 
accurate  and  admirable  treatise,  On  the  Connexion  of  the 
Physical  Sciences,  1835,  p.  411.  I  here  add  in  illustration 
of  what  has  been  said  at  page  39,  of  the  great  Aerolite  of 
the  bed  of  the  river  Narai,  the  passage  from  the  Chronicon 
Benedicti,  monachi  Sancti  Andre;e  in  Monte  Soracte,  which 
has  been  referred  to  by  Pertz,  a  document  of  the  10th  cen- 
tury, and  that  is  preserved  in  the  Biblioteca  Chigi  at  Rome. 
The  barbarous  writing  of  the  time  is  preserved  unaltered  : 
**  Anno— 921— temporibus  doraini  Johannis  Decimi  pape,  in 
wnno  pontificatus  illius  7,  visa  sunt  signa.  Nam  juxta  ur- 
bem  Roman  lapides  plurimi  de  coelo  cadere  visi  sunt.  In 
civitate  quse  vocatur  Narnia  tarn  did  ac  tetri,  ut  nihil  aliud 
credatur,  quam  de  infernalibus  locis  deducti  essent.  Nam 
ita  ex  illis  lapidibus  unus  omnium  maximus  est,  utdecidens 
in  flumen  Nanms,  ad  mensuram  unius  cubiti  super  aquas 
fluminis  usque  hodie  videretur.  Nam  et  ignitEe  faculae  de 
ccelo  plurima;  omnibus  in  hac  civitate  Romani  populi  visae 
Bunt,  ita  ut  pene  terra  contingeret,  Alise  cadentes,"  &c. — 
(Pertz,  Monum.  Germ.  hist.  Scriptores,  t.  iii.  p.  715.)  On 
the  Aerolites  of  Aegos  Potamos,  whose  fall  the  Pariscan 
Chronicle  states  to  have  happened  in  the  78"  1  Olympiad 
{Bcickh,  Corp.  Inscr.  Grsc.  t.  ii.  p.  302,  320,  and  340). 
Aristot.  Meteor,  i.  7  (Ideler,  Comm.  t.i.  p.404 — 407) ;  Stob. 
Eel.  Phys.  i.  25  p.  508,  Heeren ;  Plut.  Lys.  c.  12  ;  Diog. 
Laert.  ii.  10.  (And  aiso  under  the  Notes  39,  57, 58,  and  59. ) 
According  to  a  MongoHan  tradition,  a  black  rocky  mass,  40 
feet  in  height,  is  said  to  have  fallen  from  heaven  in  a  plain 
near  the  sources  of  the  Yellow  River  in  Western  China. — 
Abel-R6niusat,  in  Lam6therie,  Journ.  de  Phys.  1819,  Mai, 
p.  264. 

33  (p,  39.)— Biot,  Traitfe  d'Astronomie  physique,  (3me 
*d.)  1841  t.  i.  p.  149,  177,  238,  and  312.  My  immortal  friend 
Poisson  attempted  the  solution  of  the  difficulty  of  sponta- 
neous combustion  occurring  in  an  aerolite  in  a  region  where 
the  density  of  the  atmosphere  is  almost  nil,  in  a  very  pecu- 
liar manner.  He  says,  "A  une  distance  de  la  terre  oti  la 
densite  de  I'atmosphere  est  tout-A-fait  insensible,  il  serait 
difficile  d'attribuer,  coinme  on  Icfait,  I'incandesccnce  des 
aerolithes  a  uii  frottement  contre  les  moldcules  de  Tair.  Ne 
pourrait-on  pas  supposer  que  le  fluide  61ectrique  a  I'^tat 
neutre  forme  une  sorte  d'almosphere,  qui  s'etend  beaucoup 
au-dela  de  la  masse  d'air  ;  qui  est  souniise  i  I'attraction  de 
la  terre,  quoique  physiqueraent  imponderable;  et  qui  suit, 
«n  consequence,  notre  globe  dans  ses  mouvements  1  Dans 
cette  hypothese,  les  corps  dont  il  s'agit,  en  entrant  dans 
cette  atmosphere  imponderable,  d^composeraient  le  fluide 
neutre,  par  leur  action  in^gale  sur  les  deux  61ectricites,  ct 
ce  serait  en  s'electrisantqu'ils  s'^chaufferaientetdeviendra- 
ient  incandescents." — (Poisson,  Rech.  sur  la  Probability  des 
Jugements,  1837,  p.  6.) 

34  (p.  39.)— Philos.  Transact,  vol.  xxix.  p.  161—163. 

35  (p.  39.) — The  first  edition  of  Chladni's  important  treat- 
ise, On  the  origin  of  the  masses  of  Iron  discovered  by  Pallas 
and  others,  appeared  two  months  before  the  shower  of  stones 
fell  at  Siena,  and  two  years  before  Lichtenberg's  proposi- 
tion, "  that  stones  come  into  our  atmosphere  from  universal 
space,"  in  the  Gottingen  Pocket-Book. —  Vide  Olbers'  Letter 
to  Benzenberg  of  Nov.  18th,  1837,  and  the  latter's  work  on 
Falling  Stars,  p.  186. 

3G  (p.  39.)— Encke,  in  Poggend.  Annalen,  Bd.  xxxiii. 
(1834)  S.  213.  Arago,  in  Ann.  pour  1836,  p.  291.  Two  let- 
ters of  mine  to  Benzenberg,  19th  May  and  Oct.  22d,  1837, 
on  the  supposed  precession  of  the  nodes  in  the  orbit  of  the 
periodic  streams  of  shooting  stars  (Benzenb.  Sternsch.  S. 
207  and  209).  Olbers,  too,  subsequently  came  into  this 
opinion  of  the  gradual  retardation  of  the  November  phenom- 
enon (Astron.  Nachr.  1838,  No.  372,  S.  180).  If  I  venture 
to  connect  two  of  the  falls  of  shooting  stars  indicated  by  the 
Arabian  writers  with  those  discovered  by  Boguslawski,  as 
haviijg  occurred  in  the  14th  century,  I  obtain  the  following 
more  or  less  accordant  elements  of  the  nodal  movement : 

In  October  902,  in  the  night  of  the  death  of  King  Ibrahim- 
ben- Ahmed,  there  was  a  great  fall  of  stars,  "  like  a  fiery 
rain."  This  year  was  on  this  account  called  the  year  of  the 
stars. — (Conde.  Hist,  de  la  domin.  de  los  Arabes,  p.  346.) 

Oct.  19th,  1202.— Stars  fell  the  whole  night  through; 
"they  fell  like  locusts." — (Comptes-rendus,  1837,  t.  i.  p. 
294,  and  Fraehn,  in  Bull,  de  I'Acad.  de  St.  Petersbourg,  t. 
iii.  p.  308.) 

Oct.  21,  old  style,  1366,  die  sequente  post  festum  xi.  mil- 
lia  Virgiuum  ab  hora  niatutina  usque  ad  horam  priman  visa; 
sunt  quasi  stellae  de  cslo  cadere  contiuuo,  et  in  tanta  mul- 

P 


titudine,  quod  nemo  narrarc  sufficit.  This  remarkable  no- 
tice, of  which  more  use  wil'  be  made  further  on  in  the  text, 
was  discovered  by  M.von  Boguslawski,  Jun.  in  Benesse  (de 
Ilorowic)  de  W«itniil  or  Weithmiil's  Chronicon  Ecclesia 
Pragensis,  p,  389.  This  chronicle  is  republished  in  the  2«1 
part  of  the  Scriptores  rerum  Bohcmicarum  von  Pelzel  und 
Dobrowsky,  1784  (Schum.  Astr.  Nachr.  Dec.  1839). 

Night  of  Nov,  9—10,  1787,  many  shooting  stars  obsenred 
by  Hemmer  in  South  Germany,  particularly  in  Manheim. 
— (KcEmtz,  Meteorol.  iii.  237.) 

Midnight,  Nov.  12, 1799.— The  extraordinary  fall  of  stars, 
which  Bonpland  and  I  have  described,  and  which  was  ob- 
served over  the  greater  part  of  the  globe.— (Vide  Relat. 
Hist.  t.  i.  p.  519—527.) 

Nov.  12—13,  1822,  shooting  stars  mingled  with  fire-balls, 
in  great  numbers,  seen  by  Kloden,  in  Potsdam  (Gilbert's 
Annalen,  vol.  72,  p.  291). 

Nov.  13th,  1831,  at  four  a.m.,  a  great  fall  of  stars  seen  by 
Captain  B^rard  on  the  coast  of  Spain,  near  Carthagena  del 
Levante  (Annuaire,  1836,  p.  297). 

Night  of  Nov.  12—13,  1833.— The  remarkable  North 
American  phenomenon  so  admirably  described  by  Denisoa 
Olmsted. 

Night  of  Nov.  13—14, 1834.— The  same  phenomenon,  but 
not  so  brilliant,  observed  in  North  America  (Poggendorff, 
Ann.  Bd.  xxxiv.  S.  129). 

Nov.  13th,  1835,  a  stack  was  set  on  fire  by  a  single  fire- 
ball near  Belley,  D6p.  de  I'Ain  (Annuaire,  1836). 

In  the  year  1838,  the  stream  of  shooting  stars  showed  it- 
self most  decidedly  in  the  night  from  the  13th  to  the  14th 
November  (Astronom.  Nachrichten,  1838,  No.  372). 

37  (p.  39.) — It  is  not  unknown  to  me  that  of  the  62  shoot- 
ing stars  which  were  simultaneously  observed  in  Silesia,  at 
the  instance  of  Prof.  Brandes,  some  appeared  to  have  had 
an  elevation  of  'i^jgt  of  60  and  even  of  100  miles,  vide 
Brandes,  Unterhaltungen  fiir  Freunde  der  Astronomic  und 
Physik,  Heft  i.  S.  48.  But  Olbers,  by  reason  of  the  small- 
ness  of  the  parallax,  regards  all  determinations  above  30 
miles  in  height  as  doubtful. 

38  (p.  39.) — The  velocity  of,  the  planets  in  their  orbits 
varies  greatly ;  for  Mercury  it  is  6'6,  for  Venus  4*8,  and  for 
the  Earth  4*1  German  miles  per  second. 

39  (p.  40.) — Chladni  discovered  that  an  Italian  natural 
philosopher,  Paolo  Maria  Terzago,  1660,  on  the  occasion  of 
a  fall  of  aerolites  at  Milan,  in  which  a  monk  was  killed,  was 
the  first  who  spoke  of  the  possibility  of  aerolites  being  moon- 
stones :  "  Labant  philosophorum  mentes,"  says  he,  in  his 
work,  Musaeum  Septalianum,  Manfredi  Septalae,  Patricii 
Mediolanensis,  industrioso  labore  constructum,  Tortona, 
1664,  p.  44,  "sub  horum  lapidum  ponderibus ;  ni  dicere 
velimus,  lunam  terrain  alteram,  sive  mundum  esse,  ex  cujus 
monlibus  divisa  frustra  in  inferiorem  nostrum  hunc  orbem 
delabantur."  Without  having  any  knowledge  of  this  con- 
jecture, Olbers  was  led  in  the  year  1795,  after  the  great  fall 
of  stones  that  took  place  at  Siena  (16th  June,  1794),  to  the 
inquiry  of — how  great  the  original  projectile  force  must  be 
to  send  masses  from  the  moon  to  the  earth  T  And  a  prob- 
lem of  this  kind  found  occupation  for  such  minds  as  La- 
place, Biot,  Brandes,  and  Poisson,  for  some  ten  or  twelve 
years.  The  opinion  ouce  very  generally  entertained,  but 
now  abandoned,  of  the  existence  of  active  volcanoes  in  the 
moon  without  atmosphere  and  without  water,  favoured  in 
the  public  mind  the  confusion  of  a  mathematical  possibility 
with  a  physical  probability — an  explanation  of  a  physical 
fact  preferable  to  other  explanations.  Olbers,  Brandes,  and 
Chladni,  believed  that  they  had  discovered  a  refutation 
of  the  lunar  origin  of  meteoric  stones  in  the  relative  velo- 
city of  from  4  to  8  miles,  with  which  fire-balls  and  shoot- 
ing stars  enter  our  atmosphere.  To  reach  the  earth,  ac- 
cording to  Olbers,  without  bringing  the  resistance  of  the 
air  into  the  reckoning,  an  original  velocity  of  7780  feet  per 
second  were  requisite  ;  according  to  Laplace,  the  necessary 
velocity  is  7377  feet ;  according  to  Biot,  7771  feet ;  and  ac- 
cording to  Poisson,  7123  feet.  Laplace  calls  this  primary 
velocity  only  from  5  to  6  times  greater  than  that  which  a 
cannon-ball  possesses  as  it  leaves  the  gun ;  but  Olbers  has 
shown,  "  that  with  such  a  primary  velocity  of  from  7500  to 
8000  feet  per  second,  meteoric  stones  would  only  reach  the 
confines  of  our  atmosphere  with  a  velocity  of  35,000  feet" 
(1*53  German  geographical  mile).  But  as  the  measured 
velocity  of  meteoric  stones  is  in  the  mean  5  geographical 
miles,  or  more  than  114,000  feet  per  second,  they  must  ori- 
ginally have  had  a  centrifugal  force  in  the  moon  of  110,000 
feet  per  second,  fourteen  times  greater  therefore  than  La- 
place assumes.  (Olbers  in  Schum.  Jahrb.  183T,  S.  52 — 58 
und  in  Gehler's  Nues  physik.  Woterbuche,  Bd.  vi.  Abth. 
3,  S.  2129—2136.)  The  absence  of  any  resistance  from  the 
air  would,  however,  give  the  projectile  force  of  the  lunar 
volcanoes  an  advantage  beyond  the  projectile  force  of  our 
volcanoes  on  the  earth,  supposing  always  that  volcanic  ac- 
tion is  conceived  as  possible  in  the  body  of  the  moon  ;  but 
upon  the  amount  or  measure  of  the  power  of  these  lunar 
volcanoes,  we  are  still  without  any  information.    It  is  very 


114 


NOTES  TO  PRECEDING  SECTION. 


probable  indeed  that  this  amount  has  been  greatly  over-es- 
timated. A  very  accurate  observer  and  measurer  of  the 
power  of  jEtna,  Dr.  Peters,  has  found  the  greatest  velocity 
of  stones  cast  out  from  its  crater  to  be  but  1250  feet  per 
second.  Observations  on  the  Peak  of  Teneriffe  in  1798  gave 
3000  feet.  If  Laplace,  at  the  end  of  his  work  (Expos,  du 
Syst.  du  Monde,  1824,  p.  399),  says  very  considerately, 
"  que  selon  toutes  les  vraiseniblaiices  elles  vienncnt  des  pro- 
fondeurs  de  I'espace  celeste  ;"  we  still  find  him  in  another 
place,  probably  unacquainted  with  the  amazing,  wholly 
planetary  velocity  of  meteoric  stones  (Chap.  vi.  p.  233),  re- 
verting to  the  selenitic  hypothesis  with  a  kind  of  preference, 
but  always  premising  that  the  stones  cast  out  from  the 
moon  "deviennent  des  satellites  de  la  terre,  d6crivant  au- 
tour  d'elle  une  orbite  plus  ou  moins  allongee,  de  sorte  (lu'ils 
n'atteignent  I'atmosph^re  de  la  terre  qu'apres  plusieurs  et 
m^me  un  tr^s-grand  nombre  de  revolutions."  In  the  same 
way  as  an  Italian  of  Tortona  conceived  the  fancy  that  aero- 
lites came  from  the  moon,  Greek  philosophers  had  a  notion 
that  they  came  from  the  sun.  Diogenes  Laertius  (ii.  9)  ad- 
verts to  such  an  op-nion  when  treating  of  the  origin  of  the 
mass  which  fell  at  ..Egos  Potamoi  {vide  Note  32  above) ;  and 
Pliny,  who  registers  every  thing,  mentions  the  idea,  and 
ridicules  it  the  more  willingly,  because  with  earlier  writers 
(Diog.  Laert.  ii.  3  and  5)  he  excuses  Anaxagorus  for  having 
predicated  a  fall  of  stones  from  the  sun  :  "  Celebrant  Gr«oi 
AnaxagoramClazomenium  Olympiadisseptuagesimceoctavse 
secundo  annoprxdixisse  cielestium  litterarum  scientia,  qui- 
bus  diebus  saxum  casurum  esse  e  sole,  idque  factum  inter- 
diu  in  Thraciffi  parte  ad  Aegos  flumen.  Quod  si  quis  prte- 
dictum  credat,  simul  fateatur  necesse  est,  majoris  miraculi 
divinitatem  Anaxagorae  fuisse.solvique  rerum  naturte  intel- 
lectum,  et  confundi  omnia,  si  aut  ipse  Sol  lapis  esse  autun- 
quam  lapidem  in  eo  fuisse  credatur  ;  decidere  tamen  crebro 
non  eritdubium."  Anaxagoras  is  also  said  to  have  foretold 
the  fall  of  the  stone  of  smaller  dimensions,  which  was  pre- 
served in  the  Gymnasium  of  Abydos.  Falls  of  afirolites 
during  sunshine,  and  when  the  disc  of  the  moon  was  not 
visible,  probably  gave  rise  to  the  idea  of  the  sun  as  their 
source.  It  was  also  one  of  the  physical  dogmas  of  Anaxa- 
goras, and  which,  as  in  the  case  of  the  geologists  of  these 
our  own  times,  exposed  him  to  the  persecution  of  the  theo- 
logians, that  the  sun  was  "  a  molten  fiery  mass  {ixiiSpns 
iidtsvpoi)."  In  the  Phaeton  of  Euripides  the  sun.  after  the 
same  views  of  the  Clazonienaean,  is  called  a  "golden  clod," 
i.  e.,  a  fiery-coloured  luminous  mass  of  matter  ;  from  which, 
however,  we  are  not  to  conclude  that  aerolites  are  "golden 
sun-stones"  Vide  Note  31,  above;  as  also  Valckenaer, 
Diatribe  in  Eurip.  perd.  dram.  Reliquias,  1767,  p.  30.  Diog. 
Laert.  ii.  40.  We  seem,  then,  to  find  four  hypotheses 
among  the  Greek  natural  philosophers  :  a  telluric  origin  of 
falling  stars  from  ascending  vapours  ;  masses  of  stone  raised 
by  tempests,  in  Aristotle  (Meteorol.  lib.  i.  cap.  IV.  2 — 13, 
and  cap.  vii.  9)  ;  an  origin  from  the  sun ;  an  origin  from 
celestial  space,  and  as  heavenly  bodies  that  had  long  re- 
mained invisible.  On  the  last  view  of  Diogenes  of  Apol- 
lonia,  which  entirely  agrees  with  our  own,  see  the  text  (p. 
43),  and  Note  58.  It  is  remarkable  that  in  Syria,  as  a  learn- 
ed Orientalist,  my  teacher  of  Persic,  M.  Andrea  de  Nericat, 
assured  nie,  according  to  an  old  popular  belief  they  are  still 
solicitous  about  falls  of  stones  from  the  sky  in  very  clear 
moonlight  nights.  The  ancients,  on  the  contrary,  were  on 
the  watch  for  the  same  event  during  eclipses  of  the  moon 
(Plin.  xxxvii.  10,  p.  164 ;  Solinus,  o.  37  ;  Salm.  Exerc.  p. 
531)  ;  and  the  passages  collected  by  Ukert,  in  his  Geogra- 
phy of  the  Greeks  and  Romans  (Th.  ii.  1,  S.  131,  Note  14). 
On  the  improbability  that  aerolites  arise  from  gases  holding 
metallic  matters  dissolved,  which,  according  to  Fusinieri, 
exist  in  the  upper  strata  of  our  atmosphere,  and  which  pre- 
viously dispersed  in  infinite  space  had  suddenly  coalesced, 
as  well  as  on  the  penetration  and  miscibility  of  gases,  see 
my  Relation  histor.  t.  i.  p.  525. 

■fO  (p.  40.)— Bessel  in  Schum.  Astr.  Nachr.  1839,  Nr.  380 
uud  381,  S.  222  und  346.  At  the  close  of  the  work  there 
is  a  comparis(m  of  the  sun's  place  in  longitude  with  the 
epochs  of  the  November  phenomenon,  since  the  first  obser- 
vations in  Cumana,  1799. 

•*i  (p.  40.) — Dr.  Thomas  Forster  (the  Pocket  Encyclop. 
of  Natural  Phenomena,  1827,  p.  17)  informs  us  that  in 
Christ  Church  College,  Cambridge,  there  is  preserved  a 
MS.  entitled  "  Ephemerides  rerum  naturalium,"  which  is 
ascribed  to  a  monk  of  the  last  century.  In  this  MS.  natural 
phenomena  are  noted  as  having  occurred  on  every  day  of 
the  year:  the  flowering  of  plants;  the  arrival  of  birds  of 
passage,  «fec.  The  10th  of  August  is  characterized  by  the 
word  meteorodes.  This  indication  and  the  tradition  of  tho 
fiery  tears  of  St.  Lawrence,  led  Dr.  Forster  to  pay  particu- 
lar attention  to  the  August  phenomenon.— Quetelet,  Cor- 
resp.  malhem.,  s6rie  iii.  toni.  i.  1837,  p.  433. 

42  (p.  40.)— Humboldt,  Rel.hist.  t.  i.,  p.  519—527.  Elli- 
cot,  in  the  Transactions  of  the  American  Society,  1804,  vol. 
vi.  p.  29.  Arago  says  of  the  November  phenomencm, "  Ainsi 
ae  confirme  de  plus  en  plus  A  nous  I'existence  d'une  zone 
compos^e  de  millions  de  petits  corps  dont  les  orbites  rencoa- 


trent  le  plan  de  I'^cliptique  vers  le  point  que  la  terre  va  oo 
cuper  tons  les  ans.  du  II  an  13  Novenibre.  C'est  un  nou- 
veau  monde  plan6taire  qui  commence  i  se  r6v61er  t  nous." 
— Annuaire,  1836.  p.  206. 

43  (p.  40.)— Fide  Musehenbroek,  Introd.  ad  Phil.  Nat. 
1762,  t.  ii.  p.  1061.  Howard,  Climate  of  London,  vol.  ii.  p. 
23,  Observations  of  the  Year  1806,  therefore,  seven  years 
after  the  earliest  observations  of  Prof.  Brandes  (Benzenberg 
ijlier  Sternschnuppen,  S.  240—244)  ;  August-Oiiservations 
of  Thomas  Forster,  vide  Quetelet,  loc.  cit.  438 — 453  ;  of 
Adolph  Ermaii,  Buguslavvski  und  Kreil  in  Schum,  Jahrb. 
1838,  S.  317—330.  On  the  point  in  Perseus  whence  the 
stream  proceeded  on  the  lOth  of  August,  1839,  see  the  ac- 
curate measurements  of  Bessel  and  Erman  (Schum.  Astr. 
Nachr.  Nos.  385  and  428) ;  on  the  10th  of  August,  1837, 
however,  the  orbit  did  not  appear  to  be  retrograde  ;  see 
Arago,  in  C^omples  rendus,  1837,  torn.  ii.  p.  183. 

44  (p.  40.)— On  the  25th  of  April,  1095,  "innumerable 
eyes  in  France  saw  the  stars  fall  as  thick  as  hail  from 
heaven"  (ut  grando,  nisi  lucerent,  pro  densitate  putaretur  ; 
Baldr.  p.  88) ;  and  this  incident  was  regarded  by  the  Coun» 
cil  of  Clermont  as  premonitory  of  a  greaf.  movement  in 
Christendom.  (Vide  Wilken,  Gesch.  der  Kreuzziige,  Bd. 
i.  S.  75.)  On  the  22d  of  April,  1800,  a  great  fall  of  stars 
was  observed  in  Virginia  and  Massachusetts  ;  it  was  like  a 
display  of  rockets  that  lasted  for  two  hours.  Arago  first 
directed  attention  to  this  "  trainee  d'asi Oroides*' as  a  recur- 
ring phenomenon  (Annuaire,  1836,  p.  297).  The  falls  of 
aerolites  in  the  beginning  of  December  was  also  remarka- 
ble ;  their  periodical  recurrence  is  vouched  for  by  the  old 
observations  of  Brandes  in  the  night  from  the  6th  to  the  7th 
of  December,  1798,  when  he  counted  nearly  2000  falling 
stars,  and  perhaps  by  the  extraordinary  fall  of  aerolites  of 
the  11th  of  December,  1836,  at  the  village  of  Macao  on  the 
river  Assu,  Brazil  (Brande.%  Unterhalt.  fiir  Freunde  der 
Physik,  1825,  Heft  i.  S.  65,  and  Comptes  rendus,  torn.  v.  p. 
211).  Capocci,  from  1809  to  1836,  has  found  records  of 
twelve  actual  falls  of  aerolites  between  the  27th  and  the 
29th  of  November:  and  several  others  of  the  13th  of  No- 
vember, 10th  of  August,  and  16th  of  .luly  (Comptes  rendus, 
tom.  xi.  p.  357).  It  is  cumnis  that  in  the  part  of  the  earth's 
orbit  which  corresponds  to  the  months  of  .lanuary  and  Feb- 
ruary, and  perhaps  March,  no  periodical  fall  of  shooting 
stars  has  yet  been  noticed  ;  nevertheless  I  myself  observed 
a  remarkable  number  of  shooting  stars  on  the  15th  of  March, 
1803,  in  the  South  Pacific  Ocean;  and  a  shower  of  the 
same  was  seen  in  the  city  of  Quito  shortly  before  the  tre- 
mendous earthquake  of  Riobamba  (4th  Feb.  1797).  Th« 
following  epochs  deserve  the  i)articular  attention  of  ob- 
servers ; 

22-25  April, 

17  July  (17—26  July?)  (Quet.  Corr.  1837,  p.  435), 

10  August, 

12—14  November, 

27—29  November, 

6—12  December. 
The  frequency  of  these  streams,  however  great  the  differ- 
ence between  isolated  comets  and  rings  filled  with  asteroids, 
ought  not  to  excite   astonishment  when  we  think  of  th« 
depths  of  universal  space  filled  with  myriads  of  (tomets. 

45  (p.  41.) — Ferd.  v.  Wrangel,  Reise  langs  der  Nordkiist* 
von  Sibirien  in  den  Jahren  1820—1824,  Th.  ii.  S.  259.  Ob 
the  return  of  the  thicker  shower  of  the  November  asteroid.s 
every  thirty-four  years,  vide  Olbers  in  Jahrb.  1837,  S.  280. 
I  was  informed  in  Cumana,  that  shortly  before  the  dreadful 
earthquake  of  1766,  just  thirty-three  years,  therefore,  before 
the  great  exhibition  of  shooting  stars  of  November  II — 12, 
1799,  the  same  display  had  been  seen.  But  the  earthquake 
of  1766  did  not  occur  in  November,  but  on  the  21st  of  Oc- 
tol>er.  It  were  worth  the  while  of  travellers  in  Quito  to 
investigate  the  particular  day  on  which  the  volcano  Cayam- 
be  appeared  for  an  hour  as  if  enveloped  in  a  shower  of  fall- 
ing stars,  so  that  reliijious  processions  were  set  in  motion 
to  appease  the  heavens  1  {vide  mv  Relat.  histor.  t.  i.  chap, 
iv.  p.  307  ;  chap.  x.  p  520  and  527.) 

46  (p.  41.)— From  a  letter  to  me  of  January  24,  1838. 
The  extraordinary  display  of  shooting  stars  of  1799  was  ob- 
served almost  e>C;usively  in  America,  from  New  Ilerrnhut, 
in  Greenland,  to  the  Equator.  The  phenomena  of  1831  and 
1832  were  cmly  seen  in  Europe  ;  those  of  1833  and  1834 
only  in  the  United  States  of  North  America. 

47  (p.  41.;— Leltre  de  Mr.  Edouard  Biot  &  Mr.  Quetelet 
sur  les  anciennes  apparitions  d'etoiles  filantes  en  Chine,  in 
Bull,  de  I'Acad.  de  Bruxelles,  1843,  t.  x.  No.  7,  p.  8.  On 
the  notice  from  the  Chronicim  Ecclesiae  Pragensis,  vide 
Bogusiawski.  Jun.,  in  Poggend.  Aiinalen,  Bd.  xlviii.  S.  612. 
To  Note  12  should  be  added,  that  the  orbits  of  four  comets 
(568,  574,  1337,  and  1385)  have  been  reckoned  exclusively 
from  Chinese  data.  Vide  John  Russell  Hind,  in  Schunx. 
Astr.  Nachr.  1844,  Nr.  498. 

43  (p.  41.) — "  11  parait  qu'un  nombre,  qui  semble  in^pui- 
sable,  de  corps  trop  jietits  pour  6tre  observ6s,  se  meuvent 
dans  le  ciel,  soit  autour  du  soelil,  soit  autour  des  plan^tes, 
soil  peut-4tre  m£me  autour  des  satellites.     On  suppose  que 


NOTES  TO  PRECEDING  SECTION. 


115 


Joand  ces  corps  sont  recontrts  par  notre  atmosphere,  la 
iff6rence  entre  leur  vitesse  et  celle  tie  noire  plaiiete  est 
Bssez  graiide  pour  que  le  frotleraent  qu'ils  6prouvent  cniitre 
I'air,  les  ^chautfe  au  point  do  les  reiuire  incutidescents,  et 
quelquefois  de  les  faire  6clater.  Si  le  groups  des  6ti>iles 
lilantes  forme  an  anrieau  contiiiu  autourdu  soleil,  sa  vitesse 
de  circulation  pourra  Atre  tres-diff^rente  de  celle  de  la 
terre  ;  et  ses  d^placeinents  dans  le  cii'l,  par  suite  des  actions 

flan^taires,  pourrons  encore  rendre  possible  ou  impossible, 
diffiiirentes  epoques,  le  ph6nomene  de  la  rencontre  dans 
le  plan  de  l'6cliptique." — Poissou,  Recherches  sur  la  proba- 
bilit6  des  jugements,  p.  306,  307. 

O  (p.  41.) — Humboldt,  Essai  politique  sur  la  Nouv.  Es- 
pagne,  2e  6dit.)  t.  iii.  p.  310. 

60  (p.  41.)— Pliny  shows  himself  to  have  been  attentive 
to  the  colour  of  the  crust :  colore  adusto.  The  words,  lot- 
tribus  pluisse,  also  refer  to  the  burned  external  appearance 
of  Aerolites  (ii.  56  and  58). 

61  (p.  42.)— Humboldt,  Rel.  hist.  t.  ii.  chap.  xx.  p.  299— 
302. 

63  (p,  42.)— Gustav  Rose,  Reise  nach  dem  Ural,  Bd.  ii 
S.  202. 

63  (p.  42.)— Vide  Poggend.  Ann.  1825,  Bd.  iv.  S.  173— 
192.     Ranimelsberg,  Erstes  Suppl.  zum  chem.  Handworter-  j 
bache  der  Mineralogie,  1843,  s.  102,     "  It  is,"  says  the  acute  i 
Olhers,  "  a  remarkable  though  unnoticed  fact,  that  fossil  i 
meteoric  stones  have  lieen  found,  like  fossil  shells,  in  sec-  j 
ondary  and  tertiary  formations.     Shall  we  thence  feel  at  ; 
liberty  to  conclude,  that  before  the  last  and  present  ar-  | 
rangement  of  the  surface  of  our  earth,  meteoric  stones  had 
fallen  upon  it?     Schreibers  calculates  that  at  this  time  i 
there  are  about  700  falls  of  meteoric  stones  in  each  year."  j 
(Olbers,   in   Schuiu.   Jahrb.    1838,   s.    329.)      Problematic  ' 
nickeliferous  masses  of  native  iron  have  t)een  lately  found 
in   North    Asia,   (Goldseiferwerk   von   Petropawlowsk,  20  j 
Biiles  south-east  of  Kusnezk,)  at  ^distance  of  31  feet  deep,  ; 
and  in  the  Western  Carpathians  (Magura,  near  Szlanicz).  = 
Both  of  these  masses  are  extremely  like  Aerolites — Vide 
Erman,  Archiv  fiir  wisseiischaftliche   Kunde  von  Russland, 
Bd.  i.  S.  315,  and  Haidinger's  Bericht  iiber  die  Szlauiczer 
Schiirfe  in  Ungaru. 

64  (p.  42.)  — Berzelius,  Jahreslier.  Bd.  xv.  S.  217  and 
231 ;  Rammelsberg,  Handworterb.  Abth.  ii.  S.  25—28.  ! 

55  (p.  42.) — "Sir  Isaac  said,  he  took  all  the  planets  to 
be  composed  of  the  same  matter  with  this  earth,  viz.,earlh, 
water,  and  stones,  but  variously  concocted." — Turner,  Col- 
lections for  the  Hist,  of  Grantham,  cont.  authentic  Memoirs 
of  Sir  Isaac  Newton,  p.  172,  j 

56  (p.  43.)— Adolph  Erman,  in  Poggend.  Ann.  1839,  Bd.  | 
xlviii.  S.  582—601.     Biot  at  a  previous  perioi/,  (Comples 
rendus,  1836,  t,  ii.  p.  670)  raised  doubts  of  tAe  probability 
of  the  November  phenomenon  appearing  ag?in  in  the  begin- 
ning  of  May.     MSdler  has  taken  the  meon  temperature  of  j 
the  three  days  of  May  that  have  been  decried  for  the  last  j 
86  years,  according  to  Berlin  observations,  (Verhandl.  des  ; 
Vereius  zur  Be  ford,  des  Garte«baue»  1834,s.  377,)  and  finds  ; 
the  temperature  of  the  llth,  12th.  and  13th  of  May  to  re-  { 
cede  10-22  C.  precisely  at  a  season  when  the  advance  in 
the  temperature  is  the  most  rxpid.     It  would  be  very  desi- 
rable that  this  phenomena  (/  a  fall  of  temperature,  which 
there  has  been  an  obvious  disposition  to  ascribe  to  the  fu- 
sion of  masses  of  ice  in  tAe  north-east  of  Europe,  were  in- 
vestigated at  very  diffe?««iit  points  of  the  continent  of  Amer-  i 
ica,  or  in  the  southeKi  hemisphere-     Vide  Bull,  de  I'Acad.  ; 
Imp.  de  St.-Petersiourg  1843,  t.  i.  No.  4.  ! 

57  (p,  43.)— Plui.  Vitae  par.  in  Lysandro,  cap.  22.  The 
account  of  Danvtchos  (Daimachos),  according  to  which  a 
fiery  cloud  wa/  seen  for  70  days  in  succession,  and  which 
emitted  sparVs  like  falling  stars,  and  finally  sinking  down, 
de{)osited  tke  stone  of  ^gos  Potamos,  "  which  was  but  an 
insignificaAt  portion  of  the  cloud,"  is  extremely  improbable, 
because  the  course  and  direction  of  the  fire-ball  ntust  then 
have  caatinued  for  many  days  like  that  of  the  earth.  The 
fire-b»n  of  the  19th  of  July,  1686,  described  by  Halley,  per- 
formed its  visible  course  in  minutes  (Philos.  Trans,  vol. 
xi^x-  P-  163).  Whether  Daimachos,  the  writer,  -rrcpl  ev- 
tfcSeiui,  is  the  same  with  the  Daimachos  of  Platasa,  who 
WHS  sent  by  Seleucus  to  India  to  the  son  of  Androkottos,  and 
whom  Strabo  (p.  70,  Casaub.)  characterizes  as  a  ''vender 
of  lies,"  remains  uncertain.  From  another  passage  of  Plu- 
tarch (Compar.  Solonis  c.  Pop.  cap.  4),^  we  should  almost 
be  disposed  to  believe  that  he  was.     Vide  Note  32. 

58  (p.43.)— Stob.  ed.  Heeren,  i.  25,  p,  508,  Plut.  de  plac, 
Philos.  ii.  13,  ! 

69  (p.  43.)— The  remarkable  passage  of  Plutarch  (De 
plac.  Philos.  ii.  13)  is  the  following  :  "  Anaxagoras  teaches 
that  the  surrounding  ether  is  fiery  in  respect  of  its  sub- 
stance ;  and  through  the  force  of  its  circumvolution  tears 
away  masses  of  rock  from  the  earth,  sets  them  on  fire,  and 
turns  them  into  stars."  The  Clazomensan  employs  the  , 
same  kind  of  force  (centrifugal  force)  for  bringing  the  Ne- 
maean  lion  from  the  moon  to  the  Peloponnesus.  (Aelian 
xii.  7  ;  Plut.  de  facie  in  orbe  lunae,  c.  24  ;  Schol.  ex.  Cod. 
Paris,  in  Apoll.  Argon,  lib.  i.  p,  498,  ed.  Schaef.  t.  ii.  p.  t 


40;  Meineke,  Annal.  Alex.  1843,  p.  85.)  We  have  there- 
fore in  this  instance  moon  auirnals  instead  of  moon  stones. 
According  to  IVickh's  acute  remark,  the  old  myth  of  th« 
Nemsean  lion  of  the  moon  lias  an  astronomical  origin,  and  ia 
connected  symbolically  in  «.hr(»nology  with  the  intercalary 
cycles  of  the  lunar  year,  the  worship  of  the  moon  at  Ne- 
ma;a,  and  the  games  there  celebrated. 

<^  (p.  43.) — The  following  important  passage,  one  of  th« 
many  inspirations  of  Kepler  on  the  radiation  of  heat  by  the 
fixed  stars,  slow  combustum  and  the  vital  processes,  occurt 
in  the  Paralipom.  in  Vitell.  Asiron.  pars  optica,  1604, 
Propos.  xxxii.  p.  25:  "  Lucis  proprium  est  calor,  sydera 
omnia  calefaciunt.  De  syderum  luce  claritatis  ratio  testa- 
tur,  calorem  universorum  in  minori  esse  proportione  ad 
calorem  unius  solis,  quam  ut  ab  homine,  cujus  est  certa 
caloris  mensura,  uterque  simul  percipi  et  judirari  possit. 
De  cincindularum  lucula  tenuissima  iiegare  non  potes, quin 
cum  calore  sit.  Vivunt  enim  et  moventur,  hoc  autem  non 
sine  calefactione  perficitur.  Sed  neque  putrescentiura  lig- 
norura  lux  suo  calore  destituitur;  nam  ipsa  puetredo  qui- 
dam  lenlus  ignis  est.  Inest  et  slirpibus  suus  calor."  Vid« 
Kepler,  Epit,  Astron.  Copernicanae.  1618,  t.  i.  lib.  i.  p.  35. 

61  (p.  44.) — "  There  is  another  thing,  which  I  recom- 
mend to  the  observation  of  mathematical  men;  which  is, 
that  in  February,  and  for  a  little  before,  and  a  httle  after 
that  month  (as  I  have  observed  several  years  together), 
about  six  in  the  evening,  when  the  Twilight  had  almost  de- 
serted the  horizon,  you  shall  see  a  plainly  discernible  way 
of  the  Twilight  striking^  up  towards  the  Pleiades,  and 
seeming  almost  to  touch  them.  It  is  so  observed  any  clear 
night,  but  it  is  best  illic  nocte.  There  is  no  such  way  to  b« 
observed  at  any  other  lime  of  the  year  (that  i  can  perceive), 
nor  any  other  way  at  that  time  to  be  perceived  darling  up 
elsewhere.  And  I  believe  it  hath  been,  and  will  be  con- 
stantly visiWe  at  that  time  of  the  year.  But  what  the 
cause  of  it  in  nature  should  be,  I  cannot  yet  imagine,  but 
leave  it  to  further  inquiry." — Childrey,  Britannia  Baconica, 
IfiOl,  p.  183.  This  is  the  first  and  simple  account  of  the 
phenomenon,  Cassini,  D6couverte  de  la  himiere  celeste  qui 
parolt  dans  le  zodiaque,  in  the  Mem.  de  I'Acad.  t.  viii.  1730, 
p.  2r6.  Mairan,  Trait6  phys.  de  I'Aurore  bort-ale,  1754,  p. 
16.  In  the  curious  book  of  Childrey,  quoted  above,  there 
are  very  rational  views  of  the  epochs  of  the  occurrence  of 
the  maxima  and  minima  in  the  distribution  of  the  annual 
heat,  as  well  as  on  the  course  of  the  daily  temperature  ; 
and  on  the  retardation  of  the  extreme  effects  in  meteorolo- 
gical processes.  Unfortunately  the  Baconian  philosophi- 
sing Chaplain  to  Lord  Henry  Somerset,  like  Bernardin  de 
St.  Pierre,  teaches  that  the  earth  is  pointed  at  the  poles. 
Originally  he  says  it  was  glolmlar,  but  the  ceaseless  accu- 
mulation of  ice  at  the  poles  altered  the  figure  of  the  body 
of  the  earth  ;  and  as  ice  is  formed  from  water,  so  does  the 
quantity  of  water  go  on  decreasing  everywhere  else. 

62  (p.  44,) — Dominic  Cassini  (M^m.  de  I'Acad.  t.  viii. 
1730,  p.  188),  and  Mairan  (Aurore  bor.  p.  16)  even  main- 
tained that  the  phenomenon  seen  in  Persia,  in  1668,  waa 
the  zodiacal  light.  Delambre  (Hist,  de  I'Astronomie  mo- 
derne,  t.  ii.  p,  742)  ascribes  the  discovery  of  this  light  defin- 
itively to  the  traveller  Chardin  ;  but  both  in  his  Couronne- 
ment  de  Soliman  and  in  many  passages  of  his  travels  (ed. 
de  Langles,  t.  iv.  p.  326 ;  t.  x.  p.  97)  Chardin  refers  the 
Persian  niazouk  (nyzek),  ou  petite  lance,  only  to  "  la  grandc 
et  fameuse  com^te  qui  parut  presque  par  toule  la  terre  en 
1668,  et  dont  la  t^te  etoit  cach<ie  dans  I'occident,  de  sorte 
qu'on  ne  pouvoit  en  rien  apercevoirsur  I'horizon  d'Ispahan.'* 
(Atlas  du  Voyage  de  Chardin,  tab.  iv.),  from  observations 
at  Schiraz.  But  the  head  or  nucleus  of  this  comet  was 
seen  in  Brazil  and  in  India  (Pingr6,  Cometographie,  t.  ii. 
p.  22).  On  the  conjectured  identity  of  the  last  great  comet 
of  1843  with  that  which  Cassini  mistook  for  the  zodiacal 
light,  see  Schura.  Astron.  Nachr.  1843,  No.  476  and  480. 
In  the  Persian,  the  words  nizehi  ateschin  (fiery  spears  or 
lances)  are  also  used  for  the  beams  of  the  rising  or  setting 
sun ;  nayizik,  in  Freytag's  Arabic  Lexicon,  is  interpreted 
stellae  cadentes.  The  comparis(m  of  comets  with  lances  and 
spears  was,  however,  extremely  common  in  all  languages 
in  the  middle  ages.  Even  the  great  comet  which  was  seen 
from  April  to  June,  1500,  is  always  spoken  of  by  Italian 
writers  of  the  time  under  the  title  of  "il  Signor  Astone 
(vide  my  Exam.  crit.  de  I'Hist.  de  la  Geographic,  t.  v.  p. 
80).  The  statement  variously  made  that  Descartes  (Cassi- 
ni, p.  230,  Mairan,  p.  16)  and  Kepler  (Delambre,  t..i.p. 
601)  were  acquainted  with  the  zodiacal  light  appears  to  me 
altogether  untenable.  Descartes  (Principes,  iii.  art.  136, 
137)  speaks  in  a  very  obscure  manner  of  the  production  of 
comets'  tails :  "  Par  des  rayons  obliques  qui,  tombant  sur 
diverses  parties  des  orbes  plan^taires,  viennent  des  parties 
lat6rales  4  notre  oeil  par  une  refraction  extraordinaire ;" 
also  how  comets'  tails  can  be  seen  morning  and  evening, 
♦'  comme  une  longue  poutre,"  if  the  sun  be  placed  between 
the  comet  and  the  earth.  This  passage  refers  to  the  zodi- 
acal light  as  little  as  the  one  in  Kepler,  in  which  he  speaks 
of  the  existence  of  an  atmosphere  about  the  sun  (limbus 
circa  solem,  coma  lucida),  which  in  total  eclioses  of  the  sun  - 


116 


NOTES  TO  PRECEDING  SECTION. 


ht&ders  "  that  it  become  entirely  night."  Still  more  uncer- 
tain, or  rather  more  erroneous,  is  the  assertion  that  the 
"trabes  quas  6okovs  vocant''  (Plin.  ii.  22  and  27)  was  ap- 
plied to  the  ascending  tongue-shaped  zodiacal  light  as  Cas- 
(iini  (p.  231)  and  Mairan  (p.  15)  will  have  it.  Everywhere 
with  the  ancients  the  word  "trabes"  is  taken  as  synony- 
mous with  fire-balls  and  fiery-meteors  generally,  and  even 
occasionally  with  streaming  comets.  On  Sokos,  Sokios,  6o- 
KiTVi,  vide  Schafer,  Schol.  Par.  ad  Apoll.  llhod.  1813,  t.-ii. 
p.  206  ;  Pseudo-Aristot.  de  Mundo,  2,  9 ;  Comment.  Alex., 
Joh.  Philop.  et  Olymp.  in  Aristot.  Meteor,  lib.  i.  cap.  vii.  3, 
p.  195,  Ideler;  Seneca,  Nat.  Quaest.  i.  1. 

63  (p.  44.) — Humboldt,  Monumens  des  peuples  indigenes 
de  l'Am6rique,  t.  ii.  p.  301.  The  rare  MS.  which  belonged 
to  the  Archbishop  of  Rheims,  Le  Tellier,  contains  very  va- 
rious extracts  from  an  Aztekian  ritual  book,  from  an  astro- 
logical calendar,  and  from  histoi-ical  annals  from  1197  to 
1549.  The  last  include  natural  phenomena — dates  of  earth- 
quakes, comets— as  of  1490, 1592,  and,  for  Mexican  chronol- 
ogy, important  eclipses  of  the  sun.  In  the  MS.  Historia  de 
Tlascala  of  Camargo,  the  light  which  appeared  in  the  east 
and  rose  almost  to  the  zenith  is  spoken  of  as  "sparkling, 
and  as  if  thickly  sown  over  with  stars."  The  account  of 
the  40  days'  phenomenon  (Prescott,  Hist,  of  the  Conquest 
of  Mexico,  vol.  i.  p.  284)  will  by  no  means  apply  to  an  erup- 
tion of  Popocatepetl  which  rises  close  by  in  the  south-east. 
Later  commentators  have  confounded  this  phenomenon, 
which  Montezuma  regarded  as  one  foreboding  him  misfor- 
tune, to  the  "  estrella  que  humeavu"  (properly  which  spar- 
kled ;  Mexican  choloa,  to  leap,  to  sparkle).  On  the  con- 
nection of  this  vapour  with  the  star  Ciilal  Choloha  (Venus) 
and  the  starry  mountain  (Citaltepetl,  the  volcano  of  Oriza- 
ba), see  my  Monumens,  t.  ii.  p.  303. 

64  (p.  44.) — Laplace,  Expos,  du  Syst.  du  Monde,  p.  270 ; 
M6canique  celeste,  t.  ii.  p.  169  and  171.  Schubert,  Astr. 
Bd.  iii.  0  206. 

65  (p.  44.)  — Arago,  in  Annuaire,  1842,  p.  408.  See  Sir 
John  Herschel's  Considerations  on  the  Volume  and  Light 
of  the  Planetary  Nebulie,  in  Mary  Somerville's  Connexion 
of  the  Physical  Sciences,  1835,  p.  108.  The  opinion  that 
the  sun  is  a  nebulous  star,  whose  atmosphere  has  the  rip- 
pearance  of  the  zodiacal  light,  was  not  advanced  by  Cassini, 
but  by  Mairan,  1731. — {Vide  Trait6  de  I'Aurore  bor.  p.  47 
and  263.  Arago,  in  Annuaire,  1842,  p.  412.)  It  was  a  re- 
vival of  the  views  of  Kepler. 

66  (p.  45.)  —  Cassini,  as  well  as  Laplace,  Schubert  and 
Poisson  after  him,  adopted  the  hypothesis  of  a  detached 
ring  as  an  explanation  of  the  figure  of  the  zodiacal  light. 
He  says  expressly:  "  Si  les  orbites'de  Mercure  et  de  Venus 
6toient  visibles  (mat6riellement  dans  toute  I'fetendue  de 
leur  surface),  nous  les  verrions  habituellement  de  la  m^me 
figure  et  dans  la  mfeme  disposition  A  regard  du  Soleil  et 
aux  m^mes  terns  de  l'ann6e  que  la  lumiere  zodiacale." — 
(M^m.  de  I'Acad.  t.  viii.  1730,  p.  218,  and  Biot,  in  the 
Comptes  rendus,  1836,  t.  iii.  p.  666.)  Cassini  believed  that 
the  vaporiform  ring  of  the  zodiacal  light  was  composed  of 
an  innumerable  host  of  small  planetary  bodies,  which  re- 
volve about  the  sun.  He  was  himself  not  indisposed  to  be- 
lieve that  the  fall  of  fire-balls  might  be  connected  with  the 
passage  of  the  earth  through  the  zodiacal  nebulous  ring. 
Olmsted,  and  especially  Biot  (1.  c.  p.  673),  have  endeav- 
oured to  demonstrate  this  connection  with  the  November 
phenomenon  ;  any  such  connection,  however,  is  doubted  by 
Olbers  (Schum.  "Jahrb.  1837,  p.  281).  On  the  question 
whether  the  plane  of  the  zodiacal  light  perfectly  agrees 
with  the  plane  of  the  sun's  equator,  wide  Houzeau,  in  Schum. 
Astr,  Nachr.  1843,  No.  492,  p.  190. 

67  (p.  45.)— Sir  John  Herschel,  Astron.  «  487. 

68  (p.  45.)  — Arago  im  Annuaire,  1832,  p.  246. —  Many 
physical  facts  appear  to  indicate  that,  with  a  mechanical 
division  of  matter  into  its  minutest  particles,  when  the  mass 
becomes  extremely  small  in  comparison  with  the  surface, 
the  electrical  tension  may  arise  to  the  point  of  producing 
luminous  and  calorific  rays.  Experiments  with  a  large 
concave  mirror  have  not  yet  given  any  decisive  indications 
of  the  existence  of  radiating  heat  in  the  zodiacal  light. — 
(Lettre  de  Mr.  Matthiessen  k  Mr.  Arago,  in  the  Comptes 
rendus,  t.  xvi.  1843,  Avril,  p.  687.) 

69  (p.  45.)— "What  you  tell  me  of  the  variations  in  the 
light  of  the  zodiacal  light,  and  their  causes  within  the  trop- 
ics, has  interested  me  by  so  much  the  more,  as  I  have  for  a 
long  time  every  spring  given  particular  attention  to  the 
phenomenon  in  our  northern  latitudes.  I  have  myself  al- 
ways believed  that  the  zodiacal  light  rotates,  but  I  conclu- 
ded that  it  extended  with  constantly  increasing  intensity  of 
lustre  quite  to  the  sun  (in  opposition  to  Poisson's  view, 
which  you  communicate  to  me).  The  luminous  ring,  which 
shows  itself  about  the  sun  under  a  total  eclipse,  I  have  re- 
garded as  constituted  by  this  most  brilliant  portion  of  the 
zodiacal  light.  I  have  persuaded  myself  that  this  light  is 
very  different  in  different  years ;  that  for  several  years  in 
succession  it  is  extremely  bright  and  extensive  ;  in  others, 
again,  that  it  is  not  even  to  be  seen.  I  fancy  I  can  see  the  first 
indications  of  a  recognition  of  the  zodiacal  light  in  a  letter 


,  from  Rothmann  to  Tycho,  when  he  says,  that  in  the  spriltf. 

,  he  had  found  the  sun  24°  below  the  horizon  at  the  end  of 
the  evening  twilight.  Rothmann  must  certainly  have  con- 
founded the  disappearance  of  the  sinking  zodiacal  light,  in 
the  vapours  of  the  evening  horizon,  with  the  actual  end  of 
the  evening  twilight.  I  have  not  myself  observed  any  ri- 
sings and  fallings,  probably  by  reason  of  the  weakness  with 
which  the  zodiacal  light  appears  in  our  latitudes.  But  you 
are  assuredly  correct  when  you  ascribe  such  sudden  altera- 
tions in  the  light  of  the  heavenly  bodies,  which  you  ob- 
served within  the  tropics,  to  our  atmosphere,  especially  to 
changes  in  its  higher  regions.  This  is  especially  shown  in 
the  tails  of  great  comets.  One  frequently  sees,  especially 
in  clear  weather,  pulsations  in  these  tails,  which  begin  from 
the  head  of  the  comet  as  the  lowest  point,  and  tremble 
through  the  entire  length  of  the  tail  in  1  or  2  seconds,  when 
the  tail  appears  to  be  lengthened  and  immediately  after- 
wards to  be  shortened  by  several  degrees.  That  those 
pulsations,  to  which  Hooke  and  Schrocter  and  Chladni  paid 
particular  attention,  do  not  take  place  in  the  comets'  tails 
themselves,  but  are  produced  by  our  atmosphere,  becomes 
obvious  when  we  reflect  that  the  several  portions  of  the  tail 
(several  millions  of  miles  in  length)  lie  at  very  different  dis- 
tances from  us,  and  tliat  its  light  can  only  reach  us  at  in- 
tervals of  time,  several  minutes  apart  from  one  another. 
Whether  what  you  observed  on  the  Orinoco,  not  at  intervals 
of  seconds,  but  of  minutes,  were  true  corruscations  of  the 
zodiacal  light,  or  belonged  wholly  and  solely  to  the  upper 
strata  of  our  light-circle,  I  will  not  pretend  to  determine. 
Neither  do  I  know  how  the  remarkable  Inminousness  of  en- 
tire nights,  and  the  anomalous  increase  and  protraction  of 
the  twilight  in  the  year  1831,  are  to  be  explained,  espe- 
cially as  It  was  observed  that  the  brightest  parts  in  these 
extraordinary  twilights  did  not  correspond  with  the  sun's 
place  below  the  horizon." — From  a  letter  of  Dr.  Olbers  to 
me,  dated  Bremen,  26th  March,  1833. 

70  (p.  45.)  —  Biot,  Traite  d'Astron.  physique,  3me  6d., 
1841,  t.  i.  p.  171,  238.  and  312. 

71  (p.  45.)  —  Bessel,  in  Schum.  Jahrb.  fiir  1839,  S.  51  ; 
probably  one  million  of  milrs  daily  ;  in  relative  velocity, 
834.000  miles  ;  and  therefore  more  than  twice  the  velocity 
of  the  earth  in  its  orbit  round  the  sun. 

72  (p.  46.)  — On  the  Motion  of  the  Solar  System,  after 
Bradley,  Tobias,  Mayer,  Lambert,  Lalande,  and  William 
Hersc\vel,  see  Arago,  in  Annuaire,  1842.  p.  388—399;  Ar- 
gelander,  in  Schum.  Astron.  Nachr.  Nr.  363,  364,  398;  and 
in  the  treatise  :  Von  der  eigenen  Bewegung  des  Sonnensys- 
tems,  1&37,  S.  43,  on  Perseus  as  the  central  constellation 
of  the  eniire  stratum  of  stars.  See  also  Otho  Slruve,  in 
Bull,  de  I'Acad.  de  St.  Petersb.  1842,  t.  x.  No.  9,  p.  137— 
139  ;  according-  to  whom,  from  a  subsequent  combination, 
the  direction  of  the  sun's  motion  was  found  to  be  261°  23' 
R.  A.  -j-  37°  36'  Decl. ;  and,  as  a  mean  from  Argelander'a 
and  his  own  labours,  from  a  combination  of  797  stars,  2590 
9'  R.  A.  -f  340  36'  L..clination. 

73  (p.  46.)-Aristot.  (^  Ccelo,  iii.  2,  p.  301  ;  Bekker,  Phya. 
viii.  5,  p.  256. 

74  (p.  46.)— Sa vary,  in  th»  Connaissance  des  Tems,  1830, 
p.  56  and  163  ;  Encke,  Berl.  Jahrb.  1832,  S.  253  ;  Arago.  m 
Annuaire,  1834,  p.  260,  295  ;  JcHn  Herschel,  m  Mem.  of  the 
Astronom.  Soc.  vol.  v.  p.  171. 

75  (p.  46.)— Bessel,  Untersuchun^desTheils  der  plane ta- 
rischen  Storungen,  welche  aus  der  Bewegung  der  Sonnn 
entstehen,  in  Abh.  der  Berl.  Akad.  aer  Wissensch.  1824 
(Mathem.  Classe),  S.  2—6.  The  question  was  opened  up 
by  Johann  Tohias  Mayer,  in  Comment.  Soc.  Reg.  Gutting. 
1804—1808,  vol.  xvi.  p.  31—68. 

76  (p.  47.)  — Philos.  Transact,  for  1803,  p.  5.25  ;  Arago,  in 
Annuaire,  1842,  p.  375.  If  the  reader  would  Win  a  more 
tangible  idea  of  the  distance  of  the  fixed  stars  referred  to 
some  short  way  before  in  the  text,  let  him  suppose  the 
earth  to  he  at  the  distance  of  one  foot  from  the  sun, Uranus 
would  then  be  19  feet,  and  Vega  in  Lyra  34^  Gerrni.n  geo- 
graphical (158-6  English)  viiles  from  that  luminary. 

77  (p.  47.)— Bessel,  in  Schum.  Jahrbuche,  1839,  S.  5a. 

78  (p.  47.)  —  MSdler,  Astr.  S.  476 ;  Derselbe,  in  Schum. 
Jahrb.  1839,  S.  95. 

79  (p.  47.) — Sir  William  Herschel,  in  the  Philos.  Trans- 
act, for  1817,  Pt.  ii.  p.  328. 

80  (p.  47.)— Arago,  in  Annuaire,  1842,  p.  459. 

81  (p.  47.)— Sir  John  Herschel,  in  a  letter  from  Feldhuy- 
sen  of  the  13th  Jan.  !83G  ;  Nicholl,  Archit.  of  the  Heavens, 
1838,  p.  22.  See  also  some  observations  of  Sir  William 
Herschel  on  the  great  starless  space  which,  at  a  vast  dis- 
tance, separates  us  from  the  milky  way,  in  the  Philos. 
Trans,  for  1817,  Part  ii.  p.  328. 

83  (p.  47.) — Sir  John  Herschel.  Astron.  H24  ;  and  farther 
in  Observations  on  Nebulse  and  Clusters  of  Stars  (Phi). 
Trans.  1833,  Pt.  ii.  p.  479,  fig.  25) :  "  we  have  here  a  broth- 
er system,  bearing  a  real  physical  resemblance  and  strong 
analogy  of  structure  to  our  own." 

83  (p.  48.)— Sir  William  Herschel,  in  the  Transact,  for 
1785,  Pt.  i.  p.  257 ;  Sir  John  Herschel,  Astr.  §  616  ("  the 
nebulous  region  of  the  heavens  forms  a  nebulous  milky  way 


NOTES  TO  PRECEDING  SECTION. 


117 


composed  of  distinct  nebulte  as  the  other  of  stars"),  and  far- 
ther in  his  letter  to  me  of  March  1829. 

84  (p.  48.)— Sir  John  Herschcl,  Astron.  ^  585. 

86  (p.  48.)-Araffo,  in  Annuaire,  1842,  p.  282—285, 409— 
411,  and  439—442. 

86  (p.  48.)— Olbers  on  the  Transparency  of  Universal 
Space,  in  Bode's  Jahrbuch,  1826,  s.  110—121. 

87  (p.  48.)—"  An  opening  in  the  heavens."  Sir  William 
Ilerschel,  in  the  Transact,  for  1785,  vol.  Ixiv.  Pt.  i.  p.  256  ; 
Le  Francais  Lalande,  in  the  Connaissance  des  terns  pour 
I'an  viii.  p.  383  ;  Arago,  in  Annuaire,  1842,  p.  425. 

88  (p.  48.)— Aristot.  Meteor,  ii.  5,  1  ;  Seneca,  Natur. 
Quaest.  i.  14,  2  ;  "  coelum  discessisse,"  in  Cic.  de  Divin.  i.  43. 

89  (p.  48.) — Arago,  in  Annuaire,  1842,  p.  429. 

90  (p.  48  ) — In  December  1837  Sir  John  Herschel  saw  the 
star  t]  Argo,  which  had  hitherto  appeared  of  the  second  mag- 
nitude, and  quite  unchanging,  increase  rapidly  to  the  first 
niagnitude.  In  January  1838  the  intensity  of  its  light  was 
still  equal  to  that  of  a  Centauri.  According  to  the  latest  in- 
telligence, Maclear,  in  March  1843,  found  the  star  as  brill- 
iant as  Canopus :  a  Cruris  appeared  quite  misty  beside  rj 
Argo. 

91  (p.  48.) — **  Hence  it  follows  that  the  rays  of  light  of  the 
remotest  nebuliE  must  have  been  almost  tw^o  millions  of 
years  on  their  way,  and  that,  consequently,  so  many  years 
ago  this  object  must  have  had  an  existence  in  the  sidereal 
heaven,  in  order  to  send  out  those  rays  by  which  we  now 
perceive  it."  William  Herschel,  in  the  Transact,  for  1802, 
p.  498;  John  Herschel,  Astr.  ^  590;  Arugo,  in  Annuaire, 
1842,  p.  334,  359,  and  382-385. 

92  (p.  49.) — From  a  beautiful  sonnet  of  my  brother,  Frei- 
heit  und  Gesetz  (Wilhelm  von  Humboldt,  Gesammelte 
Weike,  Bd.  iv.  S.  358,  No.  25). 

93  (p.  49.)— Otfried  Muller,  Prolegomena,  S.  373. 

94  (p.  50.) — It  is  proper  to  distinguish  between  the  abso- 
lute depth  to  which  man  has  penetrated  in  his  mining  opera- 
tions, or  the  depth  from  the  surface  of  the  earth  at  the  place 
where  the  operations  are  carried  on,  and  the  relative  depth, 
i.  e.  the  depth  below  the  level  of  the  sea.  The  greatest  rel- 
ative depth  that  has  been  reached  is,  perhaps,  the  bore  at 
New-Salzwerk,  Minden,  in  Prussia.  In  June  1844  it  was 
exactly  1844A  Parisian  feet ;  the  absolute  depth  was,  how- 
ever, 2094^  Par.  feet.  The  temperature  of  the  water  in  the 
deepest  bore  was  32  7°  C.  (90  8°  F.)  which,  assuming  9  60  C. 
as  the  mean  temperature  of  the  air,  gives  a  rise  of  1-60  for 
296  metres  (upwards  of  97*6  feet  English).  The  Artesian 
well  of  Crenelle,  at  Paris,  is  only  1683  feet  in  absolute 
depth.  From  the  accounts  of  the  missionary  Imbert  from 
China,  the  depth  of  our  Artesian  wells  is  far  surpassed  by 
that  of  the  fire-spring  Ho-tsing,  which  yields  inflammable 
gas  employed  in  salt  boiling.  In  the  Chinese  province  Szii- 
tschuan,  these  fire-springs  are  said  very  commonly  to  reach 
a  depth  of  from  1800  to  2000  feet;  and  at  Tseu-lieu-tsing 
(place  of  perpetual  flax),  a  Ho-tsing,  bored  with  the  rod  in 
the  year  1812,  is  reported  to  extend  to  the  depth  of  3000 
feet  (Humboldt,  Asie  centrale,  t.  ii.  p.  521  and  525 ;  An- 
nates de  1' Association  de  la  Propagation  de  la  Foi,  1829,  No. 
16,  p.  369).  The  relative  depth  attained  at  Monte  Massi, 
in  Tuscany,  south  from  Volterra,  according  to  Matteucci,  is 
but  1 175  feet.  The  bore  at  New-Salzwerk  approaches  very 
nearly  in  relative  depth  the  coal  pit  at  Apendale,  New-cas- 
tle-under-Lyme  (Staffordshire).  There  the  works  are  car- 
ried on  725  yards,  or  2045  French  feet,  under  the  surface 
(Th.  Smith,  The  Miner's  Guide,  1836,  p.  160).  Unfortu- 
nately, the  height  of  the  ground  above  the  level  of  the  sea 
is  not  accurately  ascertained.  The  relative  depth  of  the 
Monkwearmouth  pit,  near  Newcastle-on-Tyne,  is  only  1404 
feet  (PhiUijis,  Philos.  Mag.  vol.  v.  1834,  p.  446)  ;  that  of 
the  Esperance  pit,  at  Liege,  1271  ;  and  that  of  the  lately- 
worked  pit  Marihaye,  at  Val-St.-Lambert,  is  1 157  feet.  The 
greatest  absolute  depths  to  which  man  has  penetrated  are 
in  mines,  that  are  either  among  lofty  mountains  or  in  mount- 
ain-valleys so  much  raised  above  the  sea-level  that  this  has 
either  not  been  reached  at  all  or  has  only  been  surpassed  by 
a  very  small  quantity. 

The  Eselschacht  at  Kuttenberg,  Bohemia,  before  it  was 
abondoned,  had  reached  the  enormous  depth  of  3545  feet 
(Schmidt,  Berggesetze,  Bd.  i.  S.  32).  At  St.-Daniel,  and 
at  Geist,  on  the  Rohrerbiihel,  the  works,  in  the  16th  centu- 
ry, were  2916  feet  deep.  A  drawing  of  these  workings  of 
the  year  1539  is  still  preserved.  Joseph  von  Sperges,  Ty- 
roler  Bergwerksgeschichte,  S.  121.  See  also  Humboldt, 
Gutachten  iiber  Hei-antreibung  des  Meissner  Stollens  in  die 
Freiberger  Erzrevier,  published  in  Herder  iiber  den  jetzt  be- 
gonnenen  Erbstollen,  1838,  S.  124.)  It  may  be  imagined 
that  information  of  the  extraordinary  depth  of  the  workings 
at  Rohrerbiihel  had  reached  England  at  an  early  period,  for 
in  Gilbert's  work,  De  Magnete,  I  find  the  statement  that 
roan  had  penetrated  from  2400  to  3000  feet  into  the  bowels 
of  the  earth :  "  Exigua  videtur  terrae  portio,  quae  unquam 
hominibus  spectanda  emerget  aut  eruitur :  cum  profundius 
in  ejus  viscera,  ultra  eflorescentisextremitatiscorruptelam, 
aut  propter  aquas  in  magnis  fodinis,  tanquam  per  venas  sca- 
tarientes,  aut  propter  agris  salubrioris  ad  vitam  operariorum 


sustinendam  ncccssarii  defectum,  aut  propter  ingentea 
sumptus  ad  tantos  labores  exantlandos,  multasque  difficul- 
tates,  ad  profundiores  terrae  i)urtes  penetrare  non  possumus  ; 
adeo  ut  quadringentus  aut  t<luod  rarissime]  quingentas  or- 
gyasinquibusdam  nietallis,  descendisse,  stupendus  omnibus 
videaturconatu.s"  (Gulielmi  Gilberti,  Colcestrensis,  de  Mag- 
nete Physiologia  nova,  Lond.  1600,  p.  40). 

The  absolute  depth  of  the  mines  in  the  Saxon  Erzgebirge 
are  1824  and  1714  feet ;  the  relative  depths  of  these  respect- 
ively are  only  626  and  260  feet.  The  absolute  depth  of  the 
rich  workings  in  Joachimsthal,  Bohemia,  is  1919  feet ;  but 
taking  the  height  of  the  surface  upon  Dechen's  estimate  at 
2250  feet  above  the  level  of  the  sea,  it  is  obvious  that  there 
the  sea-level  has  not  even  been  attained.  In  the  Harz,  the 
workings  in  the  Samson  pit,  at  Andreasberg,  are  carried  on 
at  the  absolute  depth  of  2062  feet.  In  Old  Spanish  Amer- 
ica I  know  of  no  deeper  mines  than  those  of  Valenciana, 
near  Guanaxuato,  Mexico :  I  found  the  Planes  de  San  Ber- 
nard 1582  feet  deep  ;  but  this  mine  does  not  reach  the  level 
of  the  sea  by  5592  feet.  If  we  compare  the  depth  of  the  old 
Kuttenberg  works  (a  depth  which  exceeds  the  height  of  the 
Brocken,  and  only  falls  short  of  that  of  Etna  by  200  feet) 
with  the  heights  of  the  loftiest  buildings  that  have  been 
reared  by  man  (the  Pyramid  of  Cheops  and  the  Minster  at 
Strasburg),  we  find  that  the  mines  are  to  these  in  the  pro- 
portion of  8  to  1. 

I  have  thought  it  important  thus  to  bring  together  these 
data  in  relation  to  the  absolute  and  relative  depths  that  have 
been  reached  by  man,  a  subject  in  connection  with  which 
many  errors  have  been  constantly  committed,  principal- 
ly, as  it  seems,  through  faulty  reductions  of  the  measure- 
ments from  one  standard  to  another.  On  proceeding  east- 
ward from  Jerusalem  towards  the  Dead  Sea,  a  prospect  is 
gained  which,  according  to  our  present  hypsometrical  knowl- 
edge, is  unparalleled  on  the  face  of  the  earth :  there,  on  ap- 
proaching the  chasm  in  which  the  Jordan  flows,  we  advance, 
in  open  day,  along  beds  of  rock  which,  according  to  Berton's 
and  Russegger's  barometrical  levellings,  lie  1300  feet  in 
perpendicular  depth  below  the  level  of  the  Mediterranean 
Sea  (vide  Humboldt,  Asie  Centrale,  t.  ii.  p.  323). 

95  (p.  50.) — Bason-shaped  curved  strata,  which  dip  down 
op  one  hand  and  rise  again  at  a  measurable  distance,  al- 
though not  penetrated  by  mines  or  shafts,  still  suffice  to  give 
us  accurate  information  of  the  constitution  of  the  crust  df 
the  earth  at  great  depths  from  the  surface.  I  have  to  thank 
the  excellent  geologist  M.  von  Dechen  for  the  following. 
He  writes  to  me :  "  The  depth  of  the  coal  measures  at 
Mont-St.-Gilles,  Liege,  which,  with  our  friend  M.  von 
Oeyenhausen,  I  have  estimated  at  3650  feet  below  the  sur- 
face, must  lie  at  the  depth  of  3250  feet  below  the  sea-level, 
inasmuch  as  Mont-St.-Gilles  is  certainly  not  400  feet  high  ; 
and  the  coal-bason  at  Mons  lies  fully  1750  feet  deeper. 
These  depressions,  however,  are  trifling  when  compared 
with  that  of  the  coal  strata  of  the  Saar  River  (Saarl)ruck). 
After  repeated  trials,  I  have  found  that  the  lowest  coal  strata 
known  in  the  country  of  Duttweiler,  near  Bettingen,  north- 
eastward from  Saarlouis,  dip  19,406  and  20,656  feet  under 
the  level  of  the  sea."  This  conclusion  exceeds  by  8000  feet 
the  estimate  which  I  have  given  in  the  text  of  Cosmos  for 
the  bason  of  Devonian  strata.  These  Belgian  coal  measures, 
therefore,  lie  as  far  below  the  level  of  the  sea  as  Chimborazo 
rises  above  it,  at  a  depth  where  the  temperature  of  the  earth 
must  be  224°  C.  (435°  F.).  From  the  highest  summit  oi 
the  Himalaya  to  the  bottom  of  this  bason,  containing  the 
vegetable  remains  of  the  primeval  world,  we  have  a  perpen- 
dicular depth  of  45,000  feet,  i.  e.  ^-i^  of  the  semi-diameter 
of  the  earth. 

96  (p.  51.)— Plato,  Phaedo,  p.  97  (Aristot.  Metaph.  p.  985). 
See  Hegel,  Philosophic  der  Geschichte,  1840,  S.  16. 

97  (p.  51.) — Bessel,  AUgemeine  Betrachtungen  iiber  Grad- 
messungennach  astronomisch-geodatischen  Arbeiten,  at  the 
end  of  Bessel  und  Baeyer's  :  Gradraessung  in  Ostpreussen, 
S.  427.  On  the  accumulation  of  matter  on  the  side  of  the 
moon  which  is  turned  to  us,  see  farther,  Laplace,  Expos, 
du  Syst.  du  Monde,  p.  308. 

98  (p.  51.)— Plin.  ii.  68;  Seneca,  Nat.  Quaest.  Praef.  c. 
ii.  "  El  Mundo  es  poco"  (the  earth  is  small)  writes  Colum- 
bus from  Jamaica  to  Queen  Isabella  on  the  7th  of  June, 
1503  ;  not  in  the  philosophical  sense  of  the  two  Romans,  but 
because  it  seemed  politic  to  him  to  represent  the  passage 
from  Spain  as  no  great  matter,  in  the  same  way  that  he 
spoke  of  "seeking  the  east  from  the  west."  Vide  my  Ex- 
amen  crit.  de  i'hist.  de  la  G6ogr.  du  15me  siecle,  t.  i.  p.  83, 
and  t.  ii.  p.  327  ;  where  I  have,  at  the  same  time,  shown 
that  the  opinion  maintained  by  Delisle,  Fr6ret,  and  Gosse- 
lin,  according  to  which  the  extraordinary  diversity  in  the 
estimates  of  the  earth's  perimeter  among  the  Greeks  is 
merely  apparent,  and  depends  on  diflTerences  of  the  stadia, 
was  already  advanced  by  Jaime  Ferrer,  in  the  year  1495,  in 
a  proposal  for  the  determination  of  the  Papal  line  of  demar- 
cation. 

99  (p.  52.)— Brewster,  Life  of  Sir  Isaac  Newton,  1831,  p 
162 :  "  The  discovery  of  the  spheroidal  form  of  Jupiter  by 


118 


NOTES  TO  PRECEDING  SECTION. 


Cassini  had  probably  directed  the  attention  of  Newton  to 
the  determination  of  its  cause,  and,  consequently,  to  the 
investigation  of  the  true  figure  of  the  earth."  Cassini 
stated  the  oblateness  of  Jupiter  at  y*-^  in  1691  (Anc.  M6m. 
de  I'Acad.  des  Sciences,  t.  ii.  p.  108)  ;  but  we  know,  through 
Lalande  (Astronnm.  3me  6d.  t.  iii.  p.  335),  that  Maralcii  pos- 
sessed several  printed  sheets  of  a  Latin  work  which  Cassini 
began,  "On  the  Spots  of  the  Planets,"  from  which  it  is  ob- 
vious that  Cassini  was  aware  of  the  oblateness  of  Jupiter 
previous  to  1666 ;  21  years,  therefore,  before  the  appear- 
ance of  Newton's  Principia. 

100  (p.  52.) — According  to  Bessel's  iiivestigation  of  ten 
measurements  of  degrees,  in  which  the  error  in  the  French 
measurement  discovered  by  Puissant  was  taken  into  account 
(vide  Schumacher,  Astron.  Nachr.  1841,  No.  438,  S.  116), 
the  semi-axis  major  of  the  elliptical  spheroid  of  rotation 
which  comes  nearest  to  the  irregular  figure  of  the  earth  is 
3272077-14  toises  ;  the  semi-axis  minor  is  3261139-33  toises  ; 
the  oblateness,  T>^-Q?yTp7  '  ^^®  length  of  the  mean  degree  of 
the  meridian,  SfOl'S-lOg"  toises,  with  an  error  of  +  2-8403 
toises ;  whence  the  length  of  a  geographical  mile  comes 
out  3807-23  toises.  Earlier  estimates  of  measurements  of 
degrees  vary  between  ^^  and  tj^tj  :  thus,  Walbeck,  de 
forma  et  magnitudine  telluris  in'deniensis  arcubus  meri- 
diani  definiendis,  makes  it  ^Tf-^f^  in  1819  ;  Ed.  Schmidt 
(Lehrbuch  der  mathem.  und  phys.  Geographic,  S.  5), 
■5^.3-^  in  1829  from  seven  measurements  of  degrees.  On 
flie  influence  of  great  differences  of  latitude  upon  the  polar 
flattening,  vide  Bibliotheque  universelle,  t.  xxxiii.  p.  181, 
and  t.  XXXV.  p.  56  ;  also,  Connaissance  des  tems,  1829,  p. 
290.  From  the  moon's  equation  alone,  Laplace  found,  first 
(Expos,  du  Syst.  p.  229),  from  the  older  tables  of  Burg 
■v^S  ;  subsequently,  from  the  lunar  observations  of  Burck- 
hardt  and  Bouvard  -^^g^.y  (M6can.  celeste,  t.  v.  p.  13  and 
43). 

101  (p.  52.) — Pendulum  experiments,  as  general  results, 
have  given,  after  the  great  expedition  of  Sabine  (1822  to 
1823,  from  the  equator  to  80°  N.  lat.),  7f^\.y  ;  from  Frey- 
cinet  (excluding  the  observations  of  lie  de  France,  Guam, 
and  Mowi),  -o-^.tt  ;  after  Foster,  o^g'g-^ ;  after  Duperrey, 
Tj-Jg-.y  ;  aftef  Liitke,  v^V-o^'  ■A-?^'"^''  these  we  have  the 
observations  between  "Formentcra  and  Dunkirk  (Connais. 
des  tems,  1816),  according  to  Mathieu,  -^rgV-^ !  ^"^  between 
Formentcra  and  Unst  Island,  according  to  Biot,  tt-s-V-tt-  Vi^e 
Baily,  Report  on  Pendulum  Experiments,  in  the  Memoirs 
of  the  Royal  Astronom.  Society,  vol.  vii.  p.  96  ;  also  Bore- 
nius,  in  Bulletin  de  I'Acad.  de  St.-P6tersbourg,  1843,  t.  i. 
p.  25. 

The  first  proposal  to  apply  the  length  of  the  pendulum 
to  the  determination  of  mass,  and  to  take  the  third  part  of 
the  seconds  pendulum  as  an  universal  pes  horarius,  or 
standard  measure  for  all  nations,  occurs  in  Huygens'  Horo- 
logium  Oscillatorium,  1673,  prop.  25.  The  same  wish  was 
reiterated  anew  in  a  public  monument  raised  under  the 
equator  by  La  Condamine,  Bouguer,  and  Godin.  On  the 
beautiful  marble  tablet  which  I  found  uninjured  in  the  quon- 
dam Jesuits'  College  at  Quito  are  these  words :  "  Penduli 
simplicis  aequiiioctialis  unius  minuti  secundi  archetypus, 
mensurae  naturalis  exemplar,  utinam  universalis  !"  From 
what  La  Condamine  says,  in  his  Journal  du  Voyage  a 
I'Equateur,  1751,  p.  163,  of  passages  unfilled  up  in  the  in- 
scription, and  a  slight  difference  with  Bouguer  concerning 
the  numbers,  I  expected  to  have  found  notable  differences 
between  the  inscription  of  the  marble  tablet  and  the  state- 
ment published  at  Paris.  On  carefully  comparing  them, 
however,  I  only  found  two  of  any  importance — "  ex  area 
graduum  3J"  instead  of  "  ex  arcu  graduum  plus  quam  tri- 
um,"  and  for  1742  the  year  1745.  This  last  statement  is 
singular, inasmuch  as  La  Condamine  returned  to  Europe  in 
Nov.  1744,  and  Bouguer  had  preceded  him  in  June,  and 
Godin  in  July.  The  most  necessary  and  useful  correction 
in  the  figures  of  the  inscription  would  be  that  of  the  astro- 
nomical longitude  of  the  town  of  Quito  (vide  my  Recueil 
d'Obs.  Astron.  t.  ii.  p.  319—354).  Nonet's  latitudes,  cut 
into  the  Egyptian  monuments,  afford  a  more  recent  instance 
of  the  danger  of  all  solemn  attempts  to  perpetuate  erroneous 
or  ill-calculated  results. 

102  (p.  52.)— On  the  increased  intensity  of  attraction  in 
the  volcanic  islands,  St.  Helena,  Ualan,  Fernando  de  No- 
ronha.  Isle  of  France,  Guaham,  Mowi,  and  Galapagos,  with 
the  exception  of  the  island  of  Rawak,  perhaps  in  consequence 
of  their  vicinity  to  the  high  land  of  New  Guinea,  vide 
Mathieu  in  Delambre,  Hist,  de  1' Astron,  au  18me  siecle, 
p.  701. 

103  (p.  52.) — Many  observations  also  show  great  irregu- 
larities in  the  length  of  the  pendulum,  which  are  ascribed 
to  local  attractions  (vide  Delambre,  Mesure  de  la  M6ridien- 
ne,  t.  iii.  p.  548  ;  Biot  in  the  M6m.  de.  1' Academic  des  Sci- 
ences, t.  viii.  1829,  p.  18, 23).    When  we  proceed  from  west 


to  east  in  the  south  of  France  and  Lombardy,  we  find  t]>« 
least  intensity  in  the  force  of  gravitation  at  Bordeaux  ;  the 
intensity  increases  rapidly  in  pl-aces  situated  to  the  east, 
Figeac,  Clermont-Ferrand,  Milan,  and  Padua,  in  which  last 
city  the  maximum  force  is  observed.  The  influence  of  tho 
southern  flanks  of  the  Alps  is  not  merely  to  be  ascribed  to 
the  general  magnitude  of  their  volume,  but  as  M.  Elie  de 
Beaumont  (Recher.  sur  las  R6vol.  de  la  surf,  du  globe,  J 830, 
p.  729.)  believes,  in  principal  part  to  the  melaphyre  and 
serpentine  which  have  raised  the  chain.  On  the  flanks  of 
Mount  Ararat,  which  with  Caucasus  lies  as  it  were  in  tVie 
centre  of  gravity  of  the  old  world,  consisting  of  Europe, 
Asia,  and  Africa,  Fedorow's  careful  pendulum  experiment* 
proclaim  not  hollows,  but  dense  volcanic  masses  (Parrot, 
Reisp  zum  Ararat,  Bd.  ii.  S.  143).  In  the  geodetic  opera- 
tions of  Carlini  and  Plana  in  Lombardy,  diflerences  of  from 
20"  to  47"-8  were  found  between  the  immediale  observa- 
tions of  latitude  and  the  results  of  these  opersitions.  Vide 
the  examples  of  Andrate  and  Mondovi,  Milan  and  Padua, 
in  the  Operations  g6od6s.  et  astron.  pour  la  mesure  d'un 
arc  du  parallele  moyen,  t.  ii.  p.  347  ;  Effemeridi  astron.  di 
Milano,  1842,  p.  57.  Milan  estimated  by  Borne,  as  it  stands 
in  the  French  trigonometrical  survey,  is  in  latitude  45°  27' 
52"  ;  whilst  immediate  astronomical  observations  make  it 
450  27'  35".  As  the  perturbations  extend  far  to  the  south 
of  the  Po  towards  Parma  (Plana,  Op6rat.  g6od6s.  t.  ii.  p. 
847),  we  may  conjecture  that  even  in  the  constitution  of  the 
soil  of  the  plain,  there  are  causes  producing  deviations. 
Struve  has  met  with  the  same  thing  in  the  flattest  parts  of 
the  east  of  Europe  (Schum.  Astron.  Nachr.  No.  164).  On 
the  influence  of  dense  masses  which  are  conceived  to  lie  at 
a  moderate  depth,  corresponding  with  the  point  of  mean  el- 
evation of  the  Alps,  see  the  an-alytical  expressions  (after 
Hossard  and  Rozet)  in  Comptes  rendus,  t.  xviii.  1844,  p. 
292,  which  may  be  compared  with  Poisson  (Traite  de  IVI6- 
canique,  t.  1.  p.  282,  2me  6d.)  The  earliest  indications  of 
the  influence  of  rocks  of  different  kinds  on  the  vibrations  of 
the  pendulum,  are  those  of  Dr.  Thomas  Young  (Phil.  Trans. 
1819,  p.  70—96).  In  the  conclusions,  from  the  length  of 
the  pendulum  in  regard  to  the  curve  of  the  earth,  the  possi- 
bility is  not  to  be  overlooked  of  the  crust  of  the  earth  having 
become  consolidated  before  metallic  and  dense  basaltic 
masses,  forced  from  the  interior,  had  approached  the  surface. 

104  (p.  52.)— Laplace,  Expos,  du  Syst.  du  Monde,  p.  231. 

105  (p.  52.)— La  Caille's  pendulum  experiments  at  the 
Cape  of  Good  Hope,  which  were  calculated  with  great  care 
by  Mathieu  (Delambre,  Hist,  de  I'Astr.  18me  siec.  p.  479), 
indicate  an  oblateness  of  -^^V-T  '  ^"*  ^''°™  numerous  com- 
parisons of  observations  under  similar  parallels  of  latitude 
in  both  hemispheres  (New  Holland  and  the  Maldives  com- 
pared with  Barcelona,  New  York,  and  Dunkirk),  there  are 
no  grounds  for  estimating  the  mean  oblateness  of  the  south 
pole  as  greater  than  that  of  the  north  pole  (Biot,  in  Mem. 
de  I'Acad.  des  Sciences,  t.  viii.  1829,  p.  39—41). 

106  (p.  53.)— The  three  methods  of  conducting  the  obser- 
vations, give  the  following  results:  1st.  From  deflection  of 
the  plumb-line  in  the  neighbourhood  of  Shehallien  in  Perth- 
shire, 4-713  by  Maskelyne,  Hutton,  and  Playfair  (1774— 
1776  and  1810)  according  to  a  method  already  proposed  by 
Newton  ;  2d.  From  vibrations  of  the  pendulum  on  mount- 
ains, 4-837  (Carlini's  observations  on  Mont  Cenis  compared 
with  Biot's  observation  at  Bordeaux,  Effemer.  astr.  di  Mi- 
lano, 1824,  p.  184) :  3rd.  From  the  torsion  balance  of  Cav- 
endish, after  an  apparatus  originally  imagined  by  Mitchell, 
5-48  (from  Hutton's  revision  of  the  calculation  5-32,  and 
from  Ed.  Schmidt's  revision  5'52 :  Lehrb.  des  mathem. 
Geographaphie,  Bd.  i.  S.  487)  ;  from  the  torsion  balance  of 
Reich,  5-44.  In  the  cnlculatiou  of  this  experiment  carried 
through,  in  a  most  masterly  manner  by  Prof.  Reich,  the 
original  mean  result  was  5-43  (with  a  probable  error  of  but 
00233) ;  a  result  which,  increased  by  the  quantity  by  which 
the  centrifugal  force  of  the  earth  diminishes  the  force  of 
gravitation,  for  the  latitude  of  Freiburg  (50°  55  ),  must  be 
changed  unto  5-44.  The  employment  of  masses  of  cast-iron 
instead  of  lead  gave  no  difference  of  result  that  might  not 
safely  be  ascribed  to  error  of  observation  ;  there  was  no  ev- 
idence of  magnetic  attraction  (Reich.  Versuche  iiber  die 
mittlere  Dichiigkeit  der  Erde,  1838,  S.  60, 62,  and  66).  By 
the  assumption  of  too  srN-all  a  degree  of  oblateness  of  the 
earth,  and  the  uncertain  estimate  of  the  density  of  the  rocks 
composing  its  surface,  a  mean  density  of  the  earth  was  come 
to,  as  in  the  experiments  on  mountains,  which  was  by  ^  too 
small,  viz.,  4-761  (Laplace,  M6can.  c61.  t.  v.  p.  46)  or  4,785 
(Eduard  Schmidt,  Lehrb.  der.  math.  Geogr.  Bd.  i.  ()  387 
and  418).  On  the  hypothesis  of  Halley,  on  the  earth  as  a 
hollow  sphere — the  germ  of  Franklin's  idea  of  earthquakes, 
vide  Phil.  Transact,  for  the  year  1693,  vol.  xvii.  p.  563. 
(On  the  structure  of  the  internal  parts  of  the  earth  and  the 
concave  habited  arch  of  the  shell.)  Halley  held  it  more 
worthy  of  the  Creator  "  that  the  earth,  like  a  house  of  sev- 
eral stories,  should  be  inhabited  both  within  and  without. 
For  light  in  the  hollow  sphere  (p.  576)  provision  could  also 
be  made  in  a  certain  way." 


NOTES  TO  PRECEDING  SECTION. 


119 


107  (p.  53.)— Here  belong  the  admirable  analytical  la- 
hours  of  Fourier,  Biot,  Laplace,  Poisson,  Duhainel,  and 
Lam6.  In  his  work. Tln'orie  mafh6mati(iue  de  la  Chaleur, 
1835,  p.  3,  428—430,  436,  and  521—524  (see  also  the 
abstract  of  La  Rive,  in  the  Bibliotheque  uuiversello  de 
Geneve,  t.  Ix.  p.  415),  Poisson  has  developed  an  hypoth- 
esis totally  different  from  the  view  advocated  by  Fou- 
rier (The<irie.  analyt.  de  la  Chaleur).  lie  denies  the 
present  fluid  state  of  the  centre  of  the  earth ;  he  believes 
"that  in  cooling  by  radiation  to  the  medium  surrounding 
the  earth,  the  parts  fuse  consolidated  on  the  surface  sank 
downwards,  and  that  by  a  double  upward  and  downward 
current,  the  great  inequality  was  lessened  which  would 
have  taken  place  in  a  solid  body  cooling  from  the  surface." 
The  great  geometrician  thinks  it  more  probable  that  the 
consolidation  commenced  in  the  parts  lying  nearer  to  the 
centre  ;  "  the  phenomenon  of  the  increase  of  heat  with  the 
depth  does  not  extend  to  the  whole  mass  of  the  earth,  and 
is  a  mere  consequence  of  the  motion  of  our  planet  in  uni- 
versal space,  the  several  parts  of  which,  by  reason  of  their 
stellar  heat  (chaleur  stellaire)  have  very  different  tempera- 
tures." The  heat  of  the  water  of  our  Artesian  wells,  ac- 
cording to  Poisson,  is  therefore  heat  which  has  penetrated 
the  body  of  the  earth  from  without ;  the  earth  may  be 
viewed  as  we  should  a  mass  of  rock  transported  from  the 
equator  to  the  pole  in  so  short  a  time,  that  it  could  not  cool 
completely.  The  increase  of  temperature  in  this  block 
would  not  extend  completely  to  its  centre.  The  physical 
doubts  which  may  reasonably  be  raised  against  this  extraor- 
dinary cosmical  hypothesis,  (an  hypothesis  which  ascribes 
to  heavenly  space  what  must  much  rather  belong  to  matter 
in  its  first  transition  from  the  gaseous  to  the  solid  state) 
may  be  found  collected  iu  Poggendorff's  Annalen,  Bd.  xxxix. 
8.  93— KtO. 

108  (p.  54.)— See  above,  pages  9,  15,  and  16.  The  in- 
crease in  temperature  is  found  in  the  Puits  de  Greneille 
from  98'4  feet ;  in  the  bore  of  New-Salzwerk,  Minden,  al- 
most 91  feet ;  at  Pr^gny,  Geneva,  also  91  feet,  although 
there  the  outlet  is  1510  feet  above  the  level  of  the  sea. 
This  agreement  of  results,  from  bores  that  are  severally 
1683,  2094,  and  680  feet  in  absolute  depth,  by  a  method  first 
suggested  in  1821  by  Arago,  (Annuaire,  1835,  p.  234)  is 
very  striking.  The  two  points  of  the  earth  at  a  short  per- 
pendicular distance  from  one  another,  whose  annual  tem- 
perature is  ascertained  with  the  greatest  precision,  are 
probably  the  external  atmosphere  of  the  Observatory  of 
Paris  and  of  the  cellar  under  the  Observatory.  The  former 
is  10O-822,  the  latter  110-834  C. ;  difference  1O012  C.  for 
86  feet  of  depth  (Poisson,  Th6orie,  &c.,  p.  415  and  462). 
lu  the  course  of  the  last  17  years,  from  causes  which  have 
not  been  ascertained,  the  thermometer  of  the  Caves  has 
risen  0O220  C.  If  the  penetration  of  waters  from  lateral 
channels  into  the  main  bore  of  Artesian  wells  produces  some 
disturbance,  it  must  be  admitted  that  in  reference  to  mines 
there  are  many  more  perturbing  causes  at  work,  and  that 
interfere  with  the  accuracy  of  conclusions  in  reference  to 
their  temperature  at  different  depths.  The  general  result 
of  Reich's  great  work  on  the  temperature  of  the  mines  of 
the  Saxon  Erzgebirge  is  the  somewhat  slow  increase  of  1° 
C.  for  128^  feet  of  descent.  (Reich,  Beob.  iiber  die  Temper- 
ature des  Gesteins  in  verschiedenen  Tiefen,  1834,  S.  134.) 
Yet  Phillips  (Poggend.  Ann.  B.  34,  S.  191),  in  a  shaft  of  the 
Monkwearmouth  coal-pit,  found  an  increase  of  1°  C.  for 
Q9-~^  feet  of  descent,  exactly  what  Arago  found  in  the  Puits 
de  Greuelle. 

109  (p.  54.) — Bous-singault  sur  la  Profondeur  4  laquelle 
se  trouve  la  Couche  de  Temperature  invariable  entre  les 
tropiques,  in  the  Annales  de  L'himie  et  de  Physique,  t.  liii. 
1833,  p.  225—247. 

110  (p.  55.)— Laplace,  Exp.  du  Syst.  du  Monde,  p.  229  and 
263 ;  Mecanique  c61.  t.  v.  p.  18  and  72.  It  is  to  be  ob- 
served that  the  fraction  y^^  of  a  centigrade  degree  of  a 
mercurial  thermometer,  which  is  given  in  the  text  as  the 
limit  of  stability  of  the  heat  of  the  earth  since  Hippar- 
chus's  time,  rests  on  the  assumption  that  the  dilatation  of 
the  materials  of  which  the  body  of  the  earth  consists  is  the 
same  as  that  of  glass  =  -^^L.-_  for  1°  C.  of  heat.  Vide 
on  this  point  Arago,  in  Annuaire  pour  1834,  p.  177 — 190. 

111  (p.  55.)— William  Gilbert  of  Colchester,  whom  Gal- 
ileo calls  "  great  to  a  degree  that  might  excite  envy,"  says, 
'•  Magnus  magnes  ipse  est  globus  terrestris."  He  ridicules 
the  magnetic  mountain  of  Fracastoro,  the  great  contempo- 
rary of  Christopher  Columbus,  as  the  magnetic  pole  :  "  Re- 
jicienda  est  vulgaris  opinio  de  moiitibus  magneticis,  aut 
rupe  aliqua  magnetica,  aut  polo  phautastico  a  polo  mundi 
distanle."  lie  assumes  the  variation  of  the  magnetic  needle 
over  the  surface  of  the  earth  as  unchanging:  "  Variatio 
uniuscujusque  loci  constans  est ;"  and  explains  the  isogonic 
lines  from  the  configuration  of  continents  and  the  relative 
position  of  the  sea  basin,  which  has  a  weaker  magnetic  at- 
tractive force  than  the  solid  masses  that  rise  above  the 
ocean  (Gilbert  de  Magnete,  ed    1633,  p.  42,  &c.) 

H2  (p.  55.)— Gauss,  Allgemeiue  Theorie   des  Erdmag- 


nctismus,  in  den  Resultaten  aus  den  Beob.  des  magnet. 
Vereins  im  Jahr.  1838,  «  41,  S.  56. 

113  (p.  55.)— There  are  also  pcrturhationx  which  do  not 
extend  to  any  distance,  which  are  more  local,  and  perhaps 
have  their  seat  less  deeply.  A  rare  example  of  such  extra- 
ordinary perturbations,  which  aie  felt  in  the  Freiburg  mines 
and  not  in  Berlin,  was  published  by  me  now  many  years 
ago  (Lettre  dc  M.  de  Humboldt  4  S.  A.  R.  le  Due  de  Sussex 
sur  les  moyens  propres  i  perfectionner  la  connaissance  du 
Magn6tismeterrestre,  in  Becquerel'sTraite  experimental  de 
TElectricite,  t.  vii.  p.  442).  Magnetic  storms  that  were  ex- 
perienced simultaneously  from  Sicily  to  Upsal,  did  not  ex- 
tend from  Upsal  to  Altona  (Gauss  and  Weber,  Resullate 
des  magnet.  Vereins,  1839,  s.  128;  Llovd,  in  the  Comptes 
rendus  de  rAcademic  des  Sciences,  t.  x'iii.  1843,  S6m.  ii.  p. 
725  and  827).  Among  the  many  perturbations  which  in 
recent  times  have  been  observed  simultaneously  over  ex- 
tensive districts  of  country,  and  which  are  collected  in  Sa- 
bine's important  work  (Observ.  on  days  of  unusual  magnetic 
disturbance,  1843),  one  of  the  most  remarkable  is  that  of 
the  25th  September,  1841,  which  was  noticed  at  Toronto  in 
Canada,  at  the  Cape  of  Good  Hope,  at  Prague,  and  partially 
in  Van  Diemeu's  Land.  The  English  Sunday,  on  which  it 
is  sinful  after  Saturday  night  at  12  o'clock  to  read  off  a 
scale,  and  to  follow  the  grand  phenomena  of  nature  in  their 
course,  intervening,  broke  off  the  observations  in  Van  Die- 
men's  Land,  and  so  made  our  information  on  this  remarkable 
storm  incomplete ! 

114  (p.  55.) — The  application  of  the  magnetic  inclination 
to  the  determination  of  the  latitude  along  a  coast  running 
north  and  south,  and  which,  like  the  shores  of  Chili  and 
Peru,  is  enveloped  in  fog  (garua)  for  a  portion  of  the  year, 
I  published  in  Lam6therie's  Journal  de  Physique,  1804,  t. 
lix.  p.  449.  The  application  in  the  locality  indicated  is  the 
more  important,  as,  in  consequence  of  the  rapid  current 
from  south  to  north  as  far  as  Cape  Parisia,  it  occasions  a 
great  loss  of  time  to  the  shipping  when  the  coast  has  to  b« 
first  approached  northward  from  the  destined  port.  In  the 
South  Sea,  from  Callao  de  Lima  harbour  to  Truxillo,  with 
a  difference  of  3°  57'  of  latitude,  I  have  observed  a  variation 
of  the  needle  of  9°  C. ;  and  from  Callao  to  Guayaquil,  with 
a  difference  of  9°  50'  of  latitude,  a  variation  of  2305°  (vide 
my  Relat.  Hist.  t.  iii.  p.  622).  From  Guarmey  (10°  4'  S. 
lat.),  Huaura  (11°  3'  S.  lat.)  to  Chancay  (11°  32'  S.  lat.), 
the  inclinations  were  6-60O,  900°,  and  10-35°.  The  deter- 
mination of  places  by  means  of  the  magnetic  inclination  had 
this  remarkable  feature  about  it,  that  where  the  ship's 
course  cuts  the  isoclinal  lines  almost  perpendicularly,  it  is 
the  only  one  that  is  independent  of  all  determination  of 
time,  and  so  of  the  sight  of  the  sun  and  other  heavenly  bod- 
ies. 1  very  lately,  and  for  the  first  time,  discovered  propo- 
sals to  determine  the  latitude  by  the  inclination  of  the 
magnetic  needle  in  Gilbert's  work,  De  Magnete  (lib.  v.  cap, 
8,  p.  200).  This  was  scarcely  20  jears  after  the  discovery 
of  magnetic  inclination  by  Robert  Norman.  Gilbert  even 
points  to  the  method  as  available  "acre  caliginoso  ;"  and 
Wright,  in  the  preface  which  he  has  added  to  the  great 
work  of  his  teacher,  speaks  of  such  a  proposal  as  '*  worth 
much  gold."  As  he,  with  Gilbert,  presumed  erroneously 
that  the  isoclinal  magnetic  lines  ran  parallel  with  the  geo- 
graphical circles  of  latitude,  as  also  that  the  magnetic  equa- 
tor coincided  with  the  geographical  equinoctial  line,  he  did 
not  perceive  that  the  proposed  method  was  only  capable  of 
a  local  and  much  more  limited  application  than  that  he  im- 
agined. 

115  (p.  55.) — Gauss  and  Weber,  Resultate  des  magnet- 
ischen  Vereins  in  J.  1838,  (f  31,  s.  46. 

116  (p  55.)— According  to  Faraday  (Loudon  and  Edin- 
burgh Philosophical  .Magazine,  1836,  vol.  viii.  p.  178),  pure 
cobalt  is  totally  without  magnetic  power.  Rose  and  Wohl- 
er,  again,  do  not  admit  this  as  absolutely  ascertained.  If 
one  of  two  masses  of  cobalt  (both  of  which  are  believed  to 
be  pure)  shows  itself  totally  indifferent  to  magnetism,  it 
seems  to  me  likely  that  the  other  which  shows  magnetic 
properties  does  so  in  virtue  of  some  impurity. 

117  (p.  55.) — Arago,  in  the  Annales  de  Chimie,  torn,  xixii. 
p.  214  ;  Brewster,  Treatise  on  Magnetism,  1837,  p.  Ill ; 
Baumgartner,  in  the  Zeitschrift  fur  Phys.  und  Mathem. 
Bd.  ii.  s.  419. 

118  (p.  55.)— Humboldt,  Examen  critique  de  I'hist.  de  la 
Geographic,  tom.  iii.  p.  36. 

119  (p.  55.)  —  Asie  centrale,  tom.  i.  Introduction,  p. 
xxxvii— xlii.  The  western  nations,  the  Greeks  and  the  Ro- 
mans, knew  that  magnetism  could  be  communicated  for  a 
great  length  of  time  to  iron  ("sola  haec  materia  ferri  vires 
a.  magnete  lapide  accipit  retinetque  longo  tempore"  Plin. 
xxxiv.  14).  The  great  discovery  of  the  terrestrial  directive 
force  therefore  depended  alone  on  this,  that  no  one  in  the 
west  happened  to  observe  a  longish  piece  of  magnetic  iron 
ore  or  a  magnetized  iron  rod,  floated  at  liberty  upon  water 
by  means  of  a  piece  of  wood,  or  balanced  and  suspended 
freely  in  the  air  by  means  of  a  thread. 

120'  (p.  56.)  —  A  very  slow  secular  progression  or  a  local 
invariability  of  the  magnetic  declination  may  be  of  great 


120 


NOTES  TO  PRECEDING  SECTION. 


consequence  in  connection  with  the  boundaries  of  property : 
•'  The  whole  mass  of  West  India  property,"  says  Sir  John 
Herschel,  "  has  been  saved  from  the  bottomless  pit  of  end- 
less litigation  by  the  invariability  of  the  magnetic  declina- 
tion in  Jamaica  and  the  surrounding-  archipelago  during  the 
whc'le  of  the  last  century ;  all  surve.ys  of  property  there 
having-  been  conducted  solely  by  the  compass."  Vide  Rob- 
ertson, in  the  Phil.  Trans,  for  1806,  pt.  ii.  p.  348,  On  the 
Permanency  of  the  Compass  in  Jamaica  since  1660.  In  the 
parent  country  (England)  the  magnetic  declination  has  va- 
ried by  14°  in  the  same  period  of  time. 

121  (p.  56.) — I  have  elsewhere  shown  that  from  the  docu- 
ments which  have  come  down  to  us  in  connection  with  the 
voyages  of  Columbus,  we  can  with  great  certainty  fix  upon 
three  places  in  the  Atlantic  line  of  no  variation  for  the  13th 
September,  1492,  the  21st  May,  1496,  and  the  16th  August, 
1498.  This  line  ran  at  these  dates  from  North-East  to 
South-West.  It  touched  the  American  continent  some- 
what to  the  east  of  Cape  Codera,  whilst  at  present  the  con- 
junction is  obser\'ed  on  the  north  coast  of  Brazil.  (Hum- 
boldt, Examen  critique  de  I'hist.  do  la  G6ogr.  torn.  iii.  p. 
44 — 48.)  From  Gilbert's  Physiologia  nova  de  Magnete,  we 
see  plainly  (and  this  fact  is  very  remarkable)  that  in  the 
year  1600  the  variation  was  still  nil  in  the  region  of  the 
Azores  (lib.  iv.  cap.  1),  precisely  as  in  Columbus's  time.  I 
believe  that,  from  documents  in  my  Examen  critique  (torn. 
iii.  p.  54),  I  have  demonstrated  that  the  celebrated  line  of 
demarcation,  by  means  of  which  Pope  Alexander  VI.  divi- 
ded the  western  hemisphere  between  Spain  and  Portugal, 
was  not  drawn  through  the  most  western  of  the  Azores,  be- 
cause Columbus  wished  to  turn  a  physical  division  into  a 
political  one.  He  indeed  laid  great  stress  nptm  the  zone 
(raya),  "on  which  the  compass  showed  no  variation,  where 
the  air  and  the  ocean,  the  latter  covered  with  sea-weed, 
show  themselves  differently  constituted,  where  cooling 
winds  begin  to  blow,  and  (for  so  erroneous  observations  of 
the  polar  star  made  him  imagine)  where  the  figure  (the 
sphericity)  of  the  earth  is  no  longer  the  same." 

122  (p.  56.)— It  is  a  question  of  the  highest  interest  in  the 
problem  of  the  physical  cause  of  the  terrestrial  magnetism, 
whether  the  two  oval  systems  of  isogonul  lines,  so  singular- 
ly included  each  within  itself,  will  continue  to  advance  for 
centuries  in  the  same  form,  or  will  resolve  themselves  and 
expand.  In  the  eastern  Asiatic  coil,  the  variation  increases 
from  without  inwards  ;  in  the  coil  or  oval  of  the  South  Sea, 
the  opposite  holds  good  ;  at  present,  indeed,  no  line  without 
variation  is  known  in  the  whole  Southern  Ocean-;  to  the 
east  of  the  meridian  of  Kamtschatka,  no  line  has  less  varia- 
tion than  2°  (Erman,  in  Poggend.  An.  b.  xxi.  s.  129).  Yet 
Cornelius  Schoutenappears,  on  Easter-day  of  the  year  1616, 
somewhat  to  the  south  of  Mukahiva.  in  15°  S.  Lat.,  132° 
W.  Long.,  in  the  middle  of  the  present  closed  isogonal  sys- 
tem, consequently,  to  have  found  the  variation  nil  (Hansteen, 
Magnetism,  der  Erde,  1819,  S.  28).  It  must  not  be  forgot- 
ten, that  in  all  these  considerations  we  can  only  follow  the 
direction  of  the  magnetic  lines  in  their  advances  as  they 
are  projected  upon  the  surface  of  the  earth. 

123  (p.  56.)— Arago,  in  Annuaire,  1836,  p.  284  :  and  1840, 
p.  330-338. 

124  (p.  56,) — Gauss,  Allg.  Theorie  des  Erdmagnetismus, 
«31. 

125  (p.  56.) — Duperrey,  de  la  configuration  de  l'6quateur 
magn6tique,  in  the  Annales  de  Chemie,  tom.  xlv.  p.  371 
and  379  (see  also  Morlet,  in  M6moires  pr6sent6s  par  di- 
rers  savans  A  I'Acad.  roy.  des  Sciences,  tom.  iii.  p.  132). 

126  (p.  57.) — See  the  remarkable  mass  of  isoclinal  lines 
in  the  Atlantic  Ocean  for  the  years  1825  an(i  1837,  in  Sa- 
bine's Contriliutions  to  Terrestrial  Magnetism,  1840,  p.  139. 

127  (p.  57.)  —  Humboldt,  iiber  die  seculSre  Verfinderung 
der  magnetischen  Inclination,  in  Poggend.  Annalen,  Bd. 
XV.  S.  322.  , 

128  (p.  57.)  —  Gauss,  Resultate  der  Beob.  des  magn.  Ve- 
reins  im  Jahr.  1838,  ^  21  ;  Sahine,  Report  on  the  Variations 
of  the  Magnetic  Intensity,  p.  63. 

139  (p.  57.) — The  following  is  the  history  of  the  discovery 
of  the  law  of  the  (general)  increase  of  intensity  in  the  mag- 
netic force  with  magnetic  latitude.  When  in  1798  I  was 
anxious  to  attach  myself  to  the  expedition  of  Captain  Bau- 
din,  fitting  out  for  a  voyage  round  the  world,  I  was  request- 
ed by  Borda,  who  took  a  warm  interest  in  my  project,  in 
different  latitudes  of  both  hemispheres,  to  observe  the  swing 
of  the  vertical  needle  in  the  magnetic  meridian,  with  a 
yiew  to  determine  whether  the  intensity  of  the  force  was 
the  same  or  different  in  different  places.  This  investiga- 
tion I  made  one  of  the  principal  points  in  the  course  of  my 
voyage  to  the  tropical  countries  of  America.  I  observed 
that  the  same  needle  which  in  Paris  performed  245,  in  Ha* 
vannah  246,  in  Mexico  242  oscillations,  in  the  course  often 
minutes  ;  at  San  Carlos,  Rio  Negro  (lOO  53'  N.  lat..  8(10  40' 
W.  long.),  in  the  same  interval  of  time,  performed  216  oscil- 
lations ;  on  the  magnetic  equator,  i.  e.  the  line  on  which 
the  inclination  is  =  0,  m  Peru  (7°  1'  S.  lat.,  80°  40'  W. 
long.), it  performed  only  211  oscillations;  in  Lima  (120  2' 
S.  lat.)  it  again  flerforiaed  219  oscillations.    1  found  further, 


from  1799  to  1803,  that  the  whole  force  taken  at  I.OOOO  on 
the  magnetic  meridian  in  the  Peruvian  Andes,  betweea 
Micuipamfia  ami  Caxamarca,  at  Paris  will  be  represented 
by  1,3482  ;  in  Mexico  by  1.3155  ;  in  San  Carlos  by  1,0480: 
in  Lima  by  1,0773.  When  I  made  known  this  law  of  tho 
variable  intensity  of  the  terrestrial  magnetic  force,  and  ad- 
duced the  numerical  value  of  observations  made  in  104  dif- 
ferent places,  in  illustration  of  the  conclusions,  in  a  paper 
which  was  read  before  the  Parisian  Institute  at  its  sitting 
of  the  26th  Frimaire,  An.  xiii.,  and  of  which  the  mathe- 
matical portion  belongs  to  M.  Biot,  the  subject  was  regarded 
as  entirely  new.  It  was  only  after  the  reading  of  this  pa- 
per, as  Biot  himself  says  expressly,  (Lam6therie,  Journ.  da 
Physique,  t.  lix.  p.  446,  note  2,)  and  as  I  repeat  the  state- 
ment in  my  Relation  Historique  (t.  i.  p.  262,  note  1),  that 
M,  de  Rossel  communicated  to  M.  Biot  his  observations  on 
oscillation  made  six  years  previously  in  Van  Dieman's 
Land,  Java,  and  Amboyna ;  from  these  observations  was 
deduced  the  same  law  of  declining  intensity  in  the  Indiaa 
Archipelago.  It  is  almost  to  be  supposed  that  this  excel- 
lent man,  in  his  own  work,  was  not  aware  of  the  regularity 
of  the  increase  and  decrease  of  the  intensity,  as  before  the 
reading  of  my  paper  he  never  mentioned  this  certainly  not 
unimportant  physical  law  to  our  common  friends.  La  Place, 
Delambre,  Prony,  and  Biot.  It  was  only  in  1808,  four  years 
after  my  return  from  America,  that  the  observations  "made 
by  M.  de  Rossel  were  published  in  the  Voyage  de  I'Entre- 
casteaux,  t.  ii.  p.  287,  291,  321,  480,  644.  Up  to  the  pres- 
ent time  it  has  still  been  usual  in  all  the  tables  of  magnetio 
intensity  that  have  been  published  in  Germany  by  Hansteen, 
Magnet,  der  Erde  1819,  s.  71 ;  Gauss,  Beob.  des  magnet.  Ve- 
reins  1838,  S.  36—39  ;  Erman,  Physikal.  Beob.  1841.  S.  529  — 
579  ;  in  England  (Sabine,  Report  on  Magnet.  Intensity,  1838, 
p.  43—62 ;  Contributions  to  Terrestrial  Magnetism,  1843,) 
and  in  France  ^Becquerel,  Trait6  d'electr.  et  de  magnet,  t. 
vii.  p.  354 — 367),  to  reduce  the  oscillations  observed  in  any 
part  of  the  earth  to  the  measure  of  the  force  which  I  found  on 
the  magnetic  equator  in  North  Peru  ;  so  that  from  the  unity 
thus  arbitrarily  assumed,  the  intensity  of  the  magnetic  force 
at  Paris  is  always  set  down  at  1,348.  Still  older  than  the  ob- 
servations of  Admiral  Rossel,  however,  are  those  that  were 
made  in  the  unfortunate  expedition  of  La  Ptirouse  by  Lama- 
non,  during  the  stay  at  Teneriffe  ( 1785)  and  to  the  arrival  at 
Macao  (1787),  and  which  were  sent  to  the  Academy  of  Scien- 
ces. It  is  known  for  certain  that  these  papers  were  in  the 
hands  of  Condorcet  in  the  July  of  1787  (Becquerel,  t.  vii.  p. 
320).  In  spite  of  searching,  however,  they  have  not  again 
been  found  ;  but  from  the  copy  of  a  letter  of  Lamanou,  now 
ill  the  possession  of  Ad.  Dui)errey,  addressed  to  the  then 
perpetual  secretary  of  the  Academy  of  Sciences,  which  has 
been  omitted  in  the  account  of  the  Voyage  of  La  Perouse, 
it  is  stated  expressly,  "  Que  la  force  attractive  de  I'aimant 
est  moindie  dans  les  tropiques  qu'en  avangant  vers  les  poles, 
et  que  I'lntensite  magnetique  deduite  du  nombre  des  oscil- 
lations de  I'aiguille  de  la  boussole  d'inclinaison  change  et 
augmente  avec  la  latitude."  Had  the  Academy  of  Sciences, 
still  anticipating  the  return  of  La  Perouse,  felt  itself  at  lib- 
erty, in  the  course  of  1787,  to  publish  an  account  of  obser- 
vations made  by  three  different  individuals  unknown  to  one 
another,  the  theory  of  terrestrial  magnetism  would  have 
been  extended  by  a  new  class  of  observations  eighteen  years 
sooner  than  it  was.  This  simple  statement  of  facts  will 
perhaps  justify  the  assertion  which  the  third  volume  of  my 
Relation  historique  (p.  615)  contains:  "Les  observations 
sur  les  variations  du  magnfetisme  terrestre  auxquelles  je  me 
suis  livre  pendant  32  ans,  au  inoyen  d'iiistrumens  compar- 
ables  entre  eux  en  Am6rique,  en  Europe  et  en  Asie,  em- 
brassent,  dans  les  deux  h«imispheres,  depuis  les  frontieres 
de  la  Dzoungarie  chinoise  jusque  vers  I'ouest  i  la  Mer  du 
Sud  qui  baigne  les  cfites  du  Mexique  et  du  Perou,  un  es- 
pace  de  188°  de  longitude,  depuis  les  60°  de  latitude  nord 
jusqu'aux  12°  de  latitude  sud.  J'ai  reganie  la  loi  du  d6- 
croissement  des  forces  magnttiques,  du  pole  a  I'fequateur, 
comme  le  r6sultat  le  plus  important  de  mon  voyage  Am6ri- 
cain."  It  is  not  certain,  but  extremely  probable,  that  Con- 
dorcet read  the  letter  of  Lamanon  of  July,  1787,  at  a  meet- 
ing of  the  Academy  of  Sciences  of  Paris  ;  and  such  a  sim- 
ple reading  I  myself  regard  as  a  sufficient  act  of  publication 
(Annuaire  du  Bureau  des  Longit.  1842,  p.  463).  The  first 
recognition  of  the  law,  therefore,  belongs  indisputiil)]y  to 
the  companion  of  La  Perouse  ;  but,  long  unheeded  or  forgot- 
ten, I  believe  that  the  knowledge  of  the  law  of  the  varia- 
tion in  the  intensity  of  the  magnetic  force  with  the  latitude, 
fir.st  acquired' a  scientific  exi.stence  with  the  publication  of 
my  observations  from  1798  to  1804.  The  subject,  and  the 
length  of  this  note,  will  not  appear  indifferent  to  him  who 
is  familiar  with  the  recent  history  of  magnetism,  and  the 
doubts  that  have  been  started  in  connection  with  it,  and 
who  from  personal  experience  knows  that  we  are  apt  to  at-  ^ 
tach  some  value  to  that  which  has  been  the  object  of  our 
uninterrupted  attention  for  five  long  years,  under  the  press- 
ure of  tropical  climates,  and  engaged  in  hazardous  mountain 
expeditions. 
130  (p.  57.) — The  maximun.  intensity  for  the  whole  »ur» 


NOTES  TO  PRECEDING  SECTION. 


121 


face  of  the  earth,  according  to  the  observations  hitherto  col- 
lected, appears  to  be  2;052,  the  minimum  0,706.  Both  phe- 
nomena l)olong  to  the  Southern  hemisphere  ;  the  first  to  73° 
47'  S.  lat.,  1690  30'  E.  long.,  near  Mount  Crozier,  West 
North-West  of  the  South  magnetic  pole,  at  a  place  where 
Sir  James  Ross  found  the  inclination  of  the  needle  87°  11' 
(Sabine,  Contributions  to  Terrestrial  Magnetism,  1843,  No. 
5,  p.  231)  ;  the  second,  observed  by  Erman  under  90°  59'  S. 
lat ,  370  24'  W.  long.,  80  miles  eastward  from  the  coast  of 
the  province  of  Espiritu  Santo,  Brazil  (Erman  Phys.  Beob. 
1841,  S.  570),  at  a  point  where  the  inclination  is  only  7°  55'. 
The  accurate  relations  of  the  intensity  to  one  another  are 
therefore  as  1  to  2-906.  It  was  long  believed  that  the  great- 
est intensity  of  the  magnetic  force  was  only  two  and  a  half 
times  as  great  as  the  weakest  which  the  surface  of  our  earth 
manifests  (Sabine,  Report  on  Intensity,  p.  82). 

131  (p.  57.) — On  Amber  (succinum,  glessum)  Pliny  says, 
xxxvii.  3,  "Genera  ejus  plura.  Attritu  digitorum  accepta 
caloris  anima  trahunt  in  se  paleas  ac  folia  arida  quae  levia 
Bunt,  ac  ut  magnes  lapis  ferri  ramenta  quoque."  (Plato,  in 
Timaeo,  p.  80  ;  Martin,  Etudes  sur  le  Timee,  t.  ii.  p.  343— 
346  ;  Strabo,  xv.  p.  703,  Casaub. ;  Clemens  Alex.  Strom, 
ii.  p.  370,  where,  strangely  enough,  to  aovxiov  and  to  t;Xc- 
xpov  are  distinguished.)  When  Thales,  in  Aristot.  de  ani- 
ma 1,  2,  and  Hippias  in  Diog.  Laertio  1,  24,  attribute  a  soul 
to  the  magnet  and  to  amber,  this  animation  only  refers  to  a 
moving  principle. 

132  (p.  57.)—"  The  magnet  attracts  iron  in  the  same  way 
as  amber  attracts  the  smallest  grains  of  mustard.  It  is  like 
a  breath  of  wind  which  penetrates  through  both,  and  is  com- 
municated with  the  rapidity  of  an  arrow."  These  words 
are  Kuopho's,  a  Chinese  orator  on  the  magnet,  and  writer  ot 
the  beginning  of  the  fourth  century.  (Klaproth,  Lettre  4 
M.A.  de  Humboldt,  sur  I'invention  de  la  boussole,  1834,  p. 
125.) 

133  (p.  58.) — "The  phenomenaof  periodical  variations  de- 
pend manifestly  on  the  action  of  solar  heat,  operating  prob- 
ably through  the  medium  of  thermoelectric  currents  induced 
on  the  earth's  surface.  Beyond  this  rude  guess,  however, 
nothing  is  as  yet  known  of  the  physical  cause.  It  is  still  a 
matter  of  speculation,  whether  the  solar  influence  be  a  prin- 
cipal or  only  a  subordinate  cause  in  the  phenomena  of  ter- 
restrial magnetism."  (Observ.  to  be  made  in  the  Antarctic 
Exped.  1840,  p.  35.) 

134  (p.  58.)— Barlow,  in  the  Philos.  Transact,  for  1822,  P. 
i.,  p.  117  ;  Sir  David  Brewster,  Treatise  on  Magnetism,  p. 
129.  Long  before  Gilbert  and  Hooke,  it  was  taught  in  the 
Chinese  work.  Ou-thsa-tsou,  that  heat  lessened  the  direct- 
ive property  of  the  magnet.  (Klaproth,  Lettre  d  M.  A.  de 
Humboldt,  sur  I'invention  de  la  boussole,  p.  96.) 

135  (p.  58.) — Vide  the  paper  on  Terrestrial  Magnetism  in 
the  Quart.  Review,  1840,  vol.  Ixvi.  p.  271—312. 

136  (p.  58.)— As  the  first  demand  for  the  establishment  of 
these  observatories  (a  net-work  of  stations  provided  with 
similar  instruments)  took  its  rise  with  me,  I  dare  not  cher- 
ish the  hope  that  I  shall  live  long  enough  to  see  both  hemi- 
spheres covered  in  equal  and  due  measure  with  magnetical 
stations,  under  the  control  of  able  naturalists  and  astrono- 
mers, and  especially  under  the  liberal  and  continued  support 
of  the  British  and  Russian  governments.  In  the  years  1806 
and  1807  at  Berlin,  with  my  friend  and  fellow  lal)ourer, 
Oltmanns,  particularly  at  the  times  of  the  solstices  and  equi- 
noxes, I  frequently  observed  the  movements  of  the  needle 
from  hour  to  hour,  and  even  from  half  hour  to  half  hour, 
during  five  or  six  days  and  nights  in  succession.  I  had  per- 
suaded myself  that  continuous,  uninterrupted  observations 
of  several  days  and  nights  were  preferable  to  the  single  ob- 
servations of  many  months.  The  apparatus,  a  magnetic 
telescope  by  Prony,  suspended  in  a  glass  case  from  a  thread 
without  torsifm,  enabled  angles  of  7  and  8  seconds  to  be 
read  off  upon  a  finely-divided  scale,  fixed  at  a  proper  dis- 
tance and  illuminated  at  night  with  lamps.  Magnetic  per- 
turbations (storms)  which  occasionally  returned  on  several 
successive  nights  at  the  same  hours,  led  me  even  at  that 
time  to  desire  most  anxiously  that  similar  apparatuses  should 
be  used  to  the  east  and  west  of  Berlin,  for  the  sake  of  dis- 
tinguishing general  telluric  phenomena  from  those  of  a  lo- 
cal nature,  and  that  may  depend  on  perturbations  in  the  un- 
equally-healed body  of  the  earth,  or  in  the  cloud-forming 
atmosphere.  My  removal  to  Paris,  and  the  lengthened  po- 
litical disturbances  which  spread  over  the  whole  of  the  west 
of  Europe,  prevented  my  wish  from  being  accomplished  at 
this  time.  The  light  diffused  by  the  great  discovery  of  Or- 
«ted  (1820),  of  the  intimate  connection  between  electricity 
and  magnetism,  finally  aroused  the  general  interest  after  its 
long  sleep,  in  the  periodical  change  of  the  electro-magnetic 
charge  of  the  earth.  Arago,  who  many  years  before  had 
begun  the  longest  unbroken  series  of  hourly  observations 
which  we  possess  in  Europe  in  the  observatory  of  Paris, 
with  an  admirable  declination  instrument  by  Gambey,  show- 
ed, by  meaus  of  simultaneous  observations  of  perturbation 
made  at  Kasan,  what  advantages  resulted  from  correspond- 
ing measurements  of  variation.  When  I  returned  to  Berlin, 
lifter.^  residence  of  eighteen  years  in  France,  I  had  a  small 


magnetic  house  erected  in  the  autumn  of  1828,  not  only  with 
a  view  to  carrying  out  the  work  begun  in  1806,  but  especial- 
ly that  simultaneous  observations,  at  hours  previously  agreed 
upon,  might  bo  made  at  Berlin,  Paris,  and  Freiburg  (at  a 
depth  of  35  fathoms  under  the  surface).  The  simultaneous- 
ness  of  the  perturbations,  and  the  parallelism  of  the  move- 
ments for  October  and  December,  1829,  were  there  graphi- 
cally represented  (Poggend.  Annal.  Bd.  xix.  S.  357,  Tab, 
I. — III.).  An  expedition  into  the  North  of  Russia,  underta- 
ken in  1829  by  command  of  the  Emperor,  gave  me  an  oppor- 
tunity of  extending  my  plan  upon  a  great  scale.  This  plan 
was  unfolded  to  a  committee  especially  named  in  one  of  the 
imperial  academies  of  science  ;  and  under  the  protection  of 
the  chief  of  the  mining  corps.  Count  von  Cancrin,  and  the 
excellent  superintendence  of  Prof.  Kupffer,  magnetic  sta- 
tions were  fixed  over  the  whole  of  the  north  of  Asia,  from 
Nicolajeff  by  Catherinenburg,  Barnaul,  and  Vertschinsk,  to 
Peking. 

The  year  1832  (vide  Getting,  gelehr.  Anzeig.  St.  206) 
marks  the  great  epoch  in  which  the  profound  author  of  anew 
theory  of  terrestrial  magnetism,  Frederick  Gauss,  erected 
apparatus,  constructed  upon  new  principles,  in  the  Gottin- 
gen  Observatory.  In  1834  the  magnetic  observatory  was 
finished,  and  in  the  same  year  Gauss  spread  his  instruments 
and  his  n^ethod  of  conducting  observations,  in  which  the 
distinguished  natural  philosopher,  William  Weber,  took 
great  interest,  over  a  large  portion  of  Germany,  Sweden, 
and  Italy  (Resultate  der  Beob.  des  magnetischen  Vereins 
im  Jahr.  1838,  S.  135,  and  Poggend.  Annalen,  Bd.  xxxiii. 
S.  426).  In  the  magnetical  association  that  was  now  form- 
ed, with  Goftingen  for  its  centre,  at  four  periods  of  the  year, 
ever  since  1836,  hourly  observations  for  an  entire  day  were 
regularly  instituted,  but  which  were  not  those  of  the  equi- 
noxes and  solstices  which  I  had  proposed  and  followed  in 
1830.  Up  to  this  time.  Great  Britain,  in  possession  of  the 
largest  commerce  in  the  world,  and  with  her  wide-spread 
navy,  had  taken  no  part  in  the  movement,  which,  since  1828, 
had  begun  to  afford  important  results  towards  the  determi- 
nation of  terrestrial  magnetism.  I  was  so  fortunate,  in  a 
public  appeal  from  Berlin  to  the  Duke  of  Sussex,  then  Pres- 
ident of  the  Royal  Society,  by  my  letter  of  April  1836,  head- 
ed, "  Lettre  de  M.  de  Humboldt  A  S.  A.  R.  le  Due  de  Sus- 
sex sur  les  moyens  propres  a  perfectionner  la  connaissance 
du  magn6tisme  terrestre  par  l'6tablissement  de  stations 
magn^tiques  et  d'observations  correspondantes,"  to  excite  a 
lively  interest  in  the  undertaking  which  had  so  long  been 
the  object  of  my  warmest  wishes.  In  my  letter  to  the  Duke 
of  Sussex  I  urged  the  erection  of  permanent  stations  in  Can- 
ada, St.  Helena,  the  Cape  of  Good  Hope,  the  Isle  of  France, 
Ceylon,  and  New  Holland,  all  of  which  I  had,  however, 
pointed  out  as  advantageous  positions  five  years  previously. 
There  was  a  joint  physical  and  meteorological  committee 
appointed  in  the  Royal  Society,  which,  besides  fixed  mag- 
netic observatories  in  both  hemispheres,  proposed  to  the 
government  to  fit  out  a  naval  expedition  for  magnetic  obser- 
vations in  the  Antarctic  Seas.  I  need  not  here  proclaim  all 
that  science  owes  in  this  conjuncture  to  the  zeal  and  activity 
of  Sir  John  Herschel,  Col.  Sabine,  Professor  Airy,  and  Mr. 
Lloyd,  as  well  as  the  powerful  support  that  was  giveii  by 
the  British  Association  for  the  Advancement  of  Science  as- 
sembled at  Newcastle  in  1838.  In  June,  1839,  the  Antarc- 
tic expedition,  under  the  command  of  Captain  James  Clarke 
Ross,  was  resolved  on  ;  and  now,  since  its  fortunate  return, 
we  enjoy  the  double  fruits  of  important  geographical  discov- 
eries in  the  neighbourhood  of  the  South  Pole,  and  a  series  of 
simultaneous  observations  in  eight  or  ten  new  magnetic  sta- 
tions. 

137  (p.  58.) — Instead  of  ascribing  the  internal  heat  of  the 
earth  to  the  transition  of  matter  from  a  state  of  gaseous  fluid- 
ity to  the  solid  condition  on  the  fonnation  of  the  planets.  Am- 
pere has  broached  what  to  me  appears  a  very  improbable 
opinion,  viz.,  that  it  might  be  a  consequence  of  an  incessant 
chemical  action  of  a  central  mass  of  earth  and  alkali-metals 
upon  the  external  crust  undergoing  oxydation.  "  On  ne  peut 
douter,"  he  says,  in  his  masterly  Theorie  des  ph6nomenes 
61ectro-dynamiques  (1826,  p.  199),  "  qu'il  existe  dans  l'int6- 
rieur  du  globe  des  courants  electro-magnetiques,  et  que  ces 
courants  sont  la  cause  de  la  chaleur  qui  lui  est  j)ropre.  lis 
naissent  d'un  noyau  metallique  central  compos6des  mfetaux 
que  Sir  Humphrey  Davy  nous  a  fait  connaltre,  agissant  sur 
la  couche  oxid6e  qui  entoure  le  noyau." 

138  (p.  58.)  —  The  remarkable  connection  between  the 
curvature  of  magnetic  lines  and  that  of  my  isothermal  lines 
was  first  observed  by  Sir  David  Brewster  (Transactions  of 
the  Royal  Society  of  Edinburgh,  vol.  ix.  1821,  p.  318,  and 
Treatise  on  Magnetism,  1837,  p.  42, 44,  47,  and  268).  This 
distinguished  natural  philosopher  admits  two  "poles  of 
maximum  cold"  in  the  northern  hemisphere  ;  one  American 
(730  N.  Lat.,  102°  W.  Long.,  near  Cape  Walter)  ;  another 
Asiatic  (73°  N.  lat.,  78^  E.  Long.)  ;  whence,  according  to 
him,  arise  two  hot  and  two  cold  meridians,  i.  e.  meridians 
of  greatest  heat  and  greatest  cold.  In  the  16th  century, 
however,  Acosta  (Hist.  nat.  de  las  Indias,  1589,  lib.  i.  cap. 
17),  resting  what  he  says  on  the  observations  of  a  highly 


122 


NOTES  TO  PRECEDING  SECTION. 


experienced  Portuguese  pilot,  taught  that  there  were  four 
lines  witliout  variation.  This  view  apjiears,  if  we  may 
judge  from  the  controversy  of  Henry  Bond  (author  of  the 
worlc — The  Longitude  Found,  1676)  with  Beckborrow,  to 
have  had  some  influence  upon  Halley's  Theory  of  magnetic 
poles.  Vide  my  Examen  critique  de  I'hist.  de  la  Geo- 
graphic, t.  iii.  p.  60. 

139  (p.  58.)— Halley,  in  the  Philosophical  Transactions, 
vol.  xxix.  (for  1714—1716,  No.  341). 

140  (p.  58.)— Dove,  in  Poggendorff's  Annalen,  Bd.  xx.  S. 
341,  Bd.  xix.  S.  388:  "The  dipping  needle  comports  itself 
very  nearly  as  an  atmospherical  thermometer,  whose  differ- 
ence in  like  manner  shows  the  increased  tension  of  the 
electricity  before  this  has  risen  to  such  a  height  that  a 
spark  is  elicited.  Vide  also  the  excellent  observations  of 
Prof.  Kaemtz,  in  his  Lehrbuch  der  Meteorologie,  Bd.  iii.  S. 
511—519;  Sir  David  Brewster,  Treatise  on  Magnetism,  p. 
280.  On  the  magnetic  properties  of  the  galvanic  flame  or 
luminous  bow  from  a  Bunsen's  charcoal  und  zinc  battery, 
vide  Casselmann's  Beob.     (Marburg,  1814,)  S.  56—62. 

141  (p.  59.)— Argelander's  import^ant  observations  on  the 
Northern  Lights,  embodied  in  his  VortrSge,  crehalten  in  der 
physikalisch-okononiischcn  Gesellschaft  zu  K6nigsberg,  Bd. 
i.  1834,  S.  257—264. 

143  (p.  59.) — On  the  results  of  the  observations  of  Lottin, 
Bravais,  and  Siljerstrom,  who  passed  a  winter  at  Bosekop, 
on  the  coast  of  Lapland  (70°  N.  Lat.),  and  in  210  nights 
saw  160  Auroras  boreales,  vide  Coniptes  rendus  de  I'Acad. 
des  Sciences,  toni.  x.  p.  289,  and  Martin's  Met6orologie, 
1843,  p.  453.  See  also  Argelander,  in  his  Vortrftge,  geh. 
in  der  Konigsberg.  Gesellschaft,  Bd.  i.  S  259. 

1415  (p.  59.) — John  Franklin  (Narrative  of  a  Joumev  to 
the  Shores  of  the  Polar  Sea  in  the  years  1819—1822,  p.' 552 
and  597;  Thieneniann,in  Edinburgh  Philosophical  Journal, 
vol.  IX.  p.  366;  Farquharson,  ib.  vol.  vi.  p.  392;  Wrangel, 
Phys.  Beob.  S.  59  ;  Parry,  Journal  of  a  Second  Voyage, 
performed  in  1821—1823,  p.  156)  saw  a  great  Aurora  con- 
tinue through  the  day.  Something  of  the  same  kind  was 
seen  in  England,  9th  Sept.  1827.  At  mid-day,  a  luminous 
arch,  20°  high,  and  rays  shooting  from  it,  were  perceived 
after  rain,  in  a  part  of  the  heavens  that  had  become  clear. 
Journal  of  the  Royal  Institution  of  Great  Britain,  1828, 
Jan.,  p.  429. 

144  (p.  59.) — After  my  return  from  my  American  travels. 
I  described  the  cirro-cumulus  cloud — when  it  appears  very 
regularly  divided  into  rounded  masses  as  if  by  the  agency 
of  repulsive  forces— under  the  name  of  polar  streaks  (bandes 
polaires),  because  their  perspective  point  of  convergence  is 
mostly  in  the  magnetic  meridian  in  the  first  instance,  so 
that  the  parallel  rows  of  cumuli  follow  the  magnetic  merid- 
ian. One  peculiarity  of  this  enigmatical  jthenomenon  is, 
the  swaying  hither  and  thither  of  the  point  of  convergence. 
Usually  the  streaks  are  only  completely  developed  in  one 
region  of  the  sky,  and  in  their  motion  they  are  seen  directed 
first  from  south  to  north,  and  then  gradually  veering  round 
from  east  to  west.  I  cannot  ascribe  the  advance  of  the 
zones  to  any  change  in  the  quarter  of  the  wind  in  the  supe- 
rior strata  of  the  atmosphere.  They  arise  when  the  air  is 
extremely  calm  and  the  heaven  is  particularly  serene,  and 
under  the  tropics  are  far  more  common  than  in  the  temper- 
ate and  frigid  zones.  I  have  observed  the  phenomenon 
among  the  Andes,  when  I  was  at  the  height  of  14,000  feet 
above  the  level  of  the  sea,  as  well  as  in  Northern  Asia,  in 
the  plains  of  Krasnojarski,  southward  from  Buchtarminsk, 
and  in  both  instances  so  much  alike,  that  the  natural  pro- 
cess in  virtue  of  which  it  takes  place  must  be  regarded  as 
one  of  very  extensive  prevalence.  See  the  important  ob- 
servations of  Kaemtz  (Vorlesungen  iiber  Meteorologie,  1840, 
S.  146)  ;  also  those  of  later  date,  or  Martins  and  Bravais' 
M6t6orologie,  1843,  p.  117.  In  an  exhibition  of  south  polar 
streaks  of  very  delicate  clouds,  which  Arago  observed  by 
day  on  the  23d  of  June,  1844,  at  Paris,  dark  rays  shot  up- 
wards from  .an  arch  which  was  directed  from  east  to  west. 
We  have  above  (p.  59)  referred  to  darker  polar  lights— to 
rays  bearing  some  resemblance  to  dusky  smoke. 

145  (p.  60.)— The  northern  lights  are  called  "the  merry 
dancers"  by  the  inhabitants  of  the  Shetland  Islands.  Ken- 
dal, in  Quarterly  .lourn.  of  Science,  new  series,  vol.  iv.  p.  395. 

146  (p.  60.)— See  the  admirable  work  of  Muncke,  in  the 
new  edition  of  Gehler's  Physik.  Worterbuch,  Bd.  vii.  1, 
S.  113—268,  particularly  S.  156. 

147  (p.  60.)— Farquharson,  in  Edinb.  Philos.  Journal,  vol. 
xvi.  p.  304  ;  Philos.  Transact,  for  1629,  p.  113. 

148  (p.  60.)— Kamtz,  Lehrb.  der  Meteorologie,  Bd.  iii.  S. 
498.  501. 

149  (p.  61.)— Arago  on  the  dry  fog  of  1783  and  1831,  which 
illuminated  the  night,  in  Annuaire  for  1842  ;  and  on  extra- 
ordiuarv  luminous  phenomena  in  clouds  without  storms, 
vide  Annuaire  for  1838,  p.  279. 

150  (p.  62.)— Herodotus,  iv.  28.  The  old  prejudice  (Pliny, 
ii.  80),  that  Egypt  never  suflTers  from  earthquakes,  is  an- 
swered by  the  colossal  statue  of  Memnon.  which  has  been 
again  restored  (Letronne,  La  Statue  vncale  de  Memnon, 
1833) ;  but  the  valley  of  the  Nile  does  lie  without  the  circle 


of  concussion  of  Byzantium,  the  Archipelago,  and  Syris 
(Ideler  ad  Aristot.  Meteor,  p.  684). 

151  (p.  62.)— Saint-Martin,  in  the  learned  notes  to  Le- 
beau.  Hist,  du  Bas  Empire,  t.  ix.  p.  401. 

152  (p.  62.)— Humboldt,  Asie  centrale,  t.  ii.  p.  110—118. 
On  the  difference  between  concussion  of  the  surface  and 
the  strata  lying  under  it,  vide  Gay-Lussac,  in  the  Annales 
de  Chimie  et  de  Physique,  t.  xxii.  p.  429. 

153  (p.  62.)— Tutissimum  est  cum  vibrat  crispante  ledifi- 
ciorum  crepitu  ;  et  cum  intumescit  assurgens  alternoque 
motu  residet,  innoxium  et  cum  concurrentia  teota  contrario 
ictu  arietant ;  quoniam  alter  motus  alteri  renititur.  Un- 
dantis  inclinatio  et  fluctus  more  quaedam  volutatio  infesta 
est,  aut  cum  in  unam  partem  totus  se  motus  impellit  (Plin. 
ii.  82).  ^ 

l'''4  (p.  62.) — Even  in  Italy  they  have  begun  to  acknowledge 
the  independence  of  earthquakes  of  the  state  of  the  weather, 
i.  e.  the  appearance  of  the  heavens  immediately  before  the 
concussion.  F.  Hoff'inann's  numerical  results  accord  in  all 
respects  with  the  experience  of  the  Abb6  Scina,  of  Palermo 
(Posthum.  Works,  vol.  ii.  p.  386- .S95).  1  have  myself  sev- 
eral times  observed  reddish  clouds  on  the  day  of  shocks, 
and  shortly  before  they  happened  ;  on  the  4th  Nov.  1799, 
indeed,  I  experienced  two  smart  shocks  at  the  moment  of  a 
loud  clap  of  thunder  (Relat.  Hist.  liv.  iv.  chap.  10).  Va- 
salli  Eandi,  of  Turin,  observed  Volia's  electrometer  much 
agitated  during  the  protracted  earthquake  of  Pignerol,  April 
2  to  May  17,  1808  (Journ.  de  Physique,  t.  Ixvii.  p.  291). 
But  these  signs  from  clouds,  from  altered  aerial  electricity, 
and  from  calms,  cannot  be  regarded  as  universally  signifi- 
cant, as  necessarily  connected  with  earthquakes.  In  Quito, 
Peru,  and  Chili,  as  well  as  in  Canada  and  Italy,  many 
earthquakes  are  observed  along  with  the  clearest  skies, 
with  the  freshest  land  and  sea-breezes.  But  if  no  meteoro- 
logical iniJicati(m  present  itself  on  the  day  of  the  shock,  or 
shortly  before  this  occurs,  it  seems  impossible  to  overlook 
the  influence  of  particular  seasons  (the  vernal  and  the  au- 
tumnal equinoxes),  i.  e.  the  commencement  of  the  rainy  sea- 
son after  long  drought  within  the  tropics,  and  the  change 
of  the  monsoons  according  to  popular  belief,  although  we 
cannot  perceive  the  genetical  connection  of  meteorological 
processes  with  what  takes  place  in  the  interior  of  the  earth. 
Numerical  inquiries  on  the  distribution  of  earthquakes 
throughout  the  course  of  the  year,  such  as  have  been  insti- 
tuted with  great  industry  by  Von  Hoff",  Merian,  and  Fried. 
Hofl^mann,  vouch  for  their  frequency  at  the  epochs  of  the 
equinoxes.  It  is  very  reniarkal)!e  that  Pliny  designates  au 
earthquake  a  subterraneous  thunder-storm,  not  so  much  by 
reason  of  the  rolling  noise  as  because  he  holds  tliat  the 
elastic  concussive  forces  acting  through  their  tension  accu- 
mulate in  tlie  interior  of  the  earth  when  they  are  absent  in 
the  atmosphere:  Ventos  in  causa  esse  non  dubium  reor. 
Neque  enim  unquam  intremiscunt  terrae,  nisi  sopito  marl 
caeloque  adeo  tranquillo,  ut  volatus  avium  non  pendeant, 
sul)tracto  omni  spiritu  qui  vehit ;  nee  unquam  nisi  post 
ventos  conditos,  scilicet  in  venas  et  cavernas  ejus  occulto 
afflutu.  Neque  aliud  est  in  terra  tremor,  quam  in  nube 
tonitruum  ;  nee  hiatus  aliud  quam  cum  fulmen  erumpit, 
incluso  spiritu  luctante  et  ad  libertatem  exire  nitente  (Plin. 
ii.79;  in  Seneca,  Nat.  Quaest.  vi.  4 — 31).  In  these  words 
we  see  the  germ  of  all  that  has  since  been  said  soberly,  or 
dreamed  on  the  causes  of  earthquakes. 

[Mr.  Edmonds— Cornwall  Journal  (?)— has  endeavoured 
to  connect  the  occurrence  of  earthquakes  with  the  period 
of  the  moon.  He  shows  that  a  great  number  of  the  most 
disastrous  have  occurred  the  day  after  the  first  quarter. 
— Tr.] 

iss  (p.  62.)— I  have  given  data  which  show  that  the  hour- 
ly variation  of  the  barometer  is  not  affected  before  or  after 
earthquakes,  in  my  Relat.  Hist.  t.  i.  p.  311  and  513. 

156  (p.  62.)— Humboldt,  Rel.  Hist.  t.  i.  p.  515-517. 

157  (p.  63.)—  On  the  Bramidos  of  Guanaxuato,  vide  my 
Essai  polit.  sur  Iji  Nouv.  Espagne,  t.  i.  p.  303.  The  sub- 
terraneous noises  without  any  appreciable  movement  of  the 
earth  in  the  deep  mines  or  on  the  surface  (6420  feet  above 
the  level  of  the  sea)  were  not  heard  in  the  lofty  table-lands 
in  the  neighbourhood,  Init  only  in  the  hilly  parts  of  the 
Sierra,  from  the  Cuesta  de  los  Aguilares,  not  far  from  Mar- 
sili  northward,  to  Santa  Rosa.  And  the  waves  of  sound  did 
not  reach  to  particular  parts  of  the  Sierra  6  or  7  milea 
north-west  of  Guanaxuato  to  the  other  side  of  Chichitne- 
quillo,  near  the  boiling  spring  of  San  Jos6  de  Comangillas 
Very  severe  measures  were  taken  by  the  magistracy  of  th 
mountain  town,  when  the  alarm  at  the  sounds  was  at  it» 
height.  "  14th  Jan.  1784.— The  flight  of  a  family  of  wealthy 
persons  shall  be  punished  with  a  fine  of  100  piastres  ;  that 
of  poor  persons  with  two  months'  imprisonment.  The  mi- 
litia are  empowered  to  bring  back  fugitives."  Not  the  least 
remarkable  point  is  the  opinion  which  the  gentry  (el  Ca- 
bildo)  are  to  form  from  their  belter  knowledge  :  "  The 
gentry,  in  their  wisdom  (en  su  Satddura),  will  know  when 
there  is  any  danger,  and  then  they  may  recommend  flight  ; 
for  the  present,  processions  are  all  that  are  requisite."  A 
famine  was  the  consequence  of  the  alarm  for  the  truenos  ; 


NOTES  TO  PRECEDING  SECTION. 


123 


no  one  would  venture  down  into  the  Sierra  from  the  pla- 
teaus where  corn  abounded. 

The  ancients  were  also  acquainted  with  noises  without 
earth(iuakes  (Arist.  Meteor,  ii.  ;  Plin.  ii.  80}.  The  strange 
noise  which  was  heard  from  March  1822  to  September  1B24, 
in  the  Dalmatian  island  Meleda  (4  miles  from  Ragusa),  and 
on  which  Partsch  has  thrown  so  much  light,  was  accompa- 
nied by  shocks  from  lime  to  time. 

158  (p.  64.)  —Drake,  Nat.  and  Stat.  View  of  Cincinnati, 
p.  232—238 ;  Mitchell,  in  the  Transactions  of  the  Lit.  and 
Philos.  Soc.  of  New  York.  toI.  i.  p.  281—308.  In  the  Pied- 
montese  county  of  Pignerol,  glasses  of  water  which  were 
filled  to  the  brim  continued  for  hours  in  incessant  motion. 

ii"''->  (p.  fi4.)— In  Spanish  they  say:  "rocas  que  hacen  pu- 
ente."  With  this  phenomenon  of  non-transmission  through 
superior  strata,  is  connected  the  remarkable  fact  that,  in 
the  beginning  of  the  present  century,  shocks  of  an  earth- 
quake were  felt  in  the  deep  silver  mines  of  Marienberg,  in 
the  Saxon  Erzgebirge,  which  were  not  perceived  at  all  on 
the  surface.  The  miners  rushed  up  in  alarm.  Contrari- 
wise, the  people  at  work  in  the  mines  of  Falun  and  Pers- 
berg  felt  nothing  of  the  smart  shocks  (Nov.  1823)  which 
threw  all  the  inhabitants  above  ground  into  a  state  of  great 
alarm. 

160  (p.  64.) — Sir  Alex.  Burnes,  Travels  into  Bokhara,  vol. 
1.  p.  18  ;  and  Wathen,  Mem.  on  the  Usbek  State,  Journal 
of  the  Asiatic  Soc.  of  Bengal,  vol.  iii.  p.  337. 

161  (p.  64.)— Philos.  Transact,  vol.  xlix.  p.  414. 

162  {p.  65.) — On  the  frequency  of  earthquakes  in  Cash- 
mir,  vide  Troyer's  Uebersetzung  des  alien  Radjatarangini, 
Tol.  ii.  p.  279  ;  and  the  Reise  von  Carl  v.  Hiigel,  Bd.  ii.  S.  184. 

I6;i  (p.  65.)  — Strabo,  lib.  i.  p.  100,  Casaub.  That  the 
phrase  i:r]\oh  iianvpov  voranov  does  not  mean  mud,  but 
lava,  appears  plainly  from  Strabo,  lib.  vi.  p.  412.  Vide  Wal- 
ter iiber  Abnahme  der  vulkanischen  Thfttigkeit  in  histor- 
ischen  Zeiten,  1844,  S.  25. 

164  (p.  66). — Bischoff's  comprehensive  work,  WSrmelehre 
des  inneren  Erdkorpers. 

165  (p.  66.)— On  the  Artesian  fire-springs  (Ho-tsing)  in 
China,  and  the  ancient  use  oi portable  gas,  in  bamboo  tul)es, 
in  the  city  of  Khiung-tscheu,  vide  Klaproth,  in  my  Asie 
centrale,  t.  ii.  p.  519—530. 

166  (p.  66.) — Boussingault  (Annales  de  Chimie,  t.  Iii.  p. 
181)  observed  no  escape  of  hydrochloric  acid  in  the  vol- 
canoes of  New  Granada,  whilst  Monticelli  found  this  acid 
in  enormous  quantities  during  the  eruption  of  Vesuvius  of 
1813. 

167  (p.  66.) — Humboldt,  Recueil  d'Observ.  astronomiques, 
t.  i.  p.  311  (Nivellement  barom6trique  de  la  Cordill^re  des 
Andes,  No.  206). 

163  (p.  66.) — Adolph  Brongniart,  in  the  Annales  des  Sci- 
ences natu  relies,  t.  xv.  p.  225. 

it)9  (p.  66.)— Bischoff.  op.  cit.  324,  Anm.  2. 

170  (p.  66.)— Humboldt,  Asie  centr.  t.  i.  p.  43. 

171  (p.  66.)— On  the  Theory  of  the  Isothermal  lines,  see 
the  clever  papers  of  Kupffer  in  Poggend.  Ann.  Bd.  xv.  S. 
184,  and  Bd.  xxxii.  S.  270 ;  in  the  Voyage  dans  I'Oural,  p. 
382—398  ;  and  in  the  Edinb.  Journ.  of  Science,  new  series, 
vol.  iv.  p.  355.  See  also  Kflmtz,  Lehrb.  der  Meteor.  Bd. 
ii,  S.  217  ;  and  on  the  ascent  of  the  Chthonisothermal  lines 
in  mountainous  countries,  Bischofi^,  S.  174—198. 

172  (p.  66.) — Leop.  V,  Buch  in  Poggend,  Ann.  Bd.  iii,  S. 
405. 

173  (p.  66.) — On  the  temperature  of  the  drops  of  rain  in 
Cumana,  which  falls  to  2230  c.  (7210  F.)  when  the  tem- 
perature of  the  air  shortly  before  had  been  30°— 31^0.  (86° 
— 87-8°  F.).  and  sinks  during  the  rain  to23-40C.  (751°  F.), 
vide  my  Relat.  Hist.  t.  ii.  p.  22.  The  rain-drops  as  they 
fall  change  the  temperature  they  had  on  their  production, 
which  depends  on  the  height  of  the  clouds  whence  they 
come,  and  the  heating  of  these  on  their  upjier  surface  by 
the  sun's  rays.  After  the  rain-drops,  on  their  first  forma- 
tion, by  reason  of  the  latent  caloric  of  the  vapour  becoming 
sensible,  have  acquired  a  higher  temperature  than  the  sur- 
rounding medium,  they  still  rise  somewhat  in  temperature, 
whilst,  as  they  fall  through  lower,  warmer,  and  moister 
strata  of  air,  vapour  continues  to  be  preci  pitated  upon  them, 
and  they  increase  in  size  (Bischoff,  Warmelehre,  S.  73)  ; 
but  this  rise  is  compensated  by  evaporation.  Cooling  of  the 
air  by  rain  is  effected  (setting  aside  what  probably  belongs 
to  the  electrical  processes  attending  thunder  storms)  by  the 
drops,  which  are  themselves  of  lower  temperature,  in  con- 
sequence of  the  place  of  their  formation,  and  farther  bring 
down  a  portion  of  the  higher  colder  air  ;  and  then  by  moist- 
ening the  ground  and  giving  occasion  to  evaporation.  Such 
are  the  usual  relations  of  the  phenomenon.  When,  in  rare 
cases,  the  rain-drops  are  warmer  than  the  lower  strata  of 
the  atmosphere  (Humboldt,  Relat.  Hist.  t.  iii.  p.  513),  the 
reason  may  perhaps  be  sought  for  in  superior  warmer  cur- 
rents, or  in  a  higher  temperature  acquired  by  extended  and 
not  very  dense  clouds  exposed  to  the  action  of  the  rays  of 
the  sun.  How,  for  the  rest,  the  phenomena  of  supplement- 
ary rainbows  (explained  by  the  interferences  of  light)  are 
connected  with  the  size  of  the  falling  drops  and  their  in- 


crease, and  how  an  optical  phenomenon,  when  rightly  ob» 
.served,  may  enlighten  us  in  regard  to  a  meteorological  pro- 
cess, according  to  diversity  of  zone,  has  been  shown  with 
great  acuteness  by  Arago,  in  the  Annuaire  for  1836,  p.  300, 
174  (p.  66.)— Boussingault's  careful  experiments  satisfy 
me  that  in  the  tropics  the  temperature  of  the  ground  a  very 
short  way  below  the  surface  corresprnids  exactly  with  the 
mean  temperature  of  the  air.  I  have  pleasure  in  quoting 
the  following  table  : 


Oti.-f.>ot  on 

.Mean  temper 
afure  of 

Height  Hbove  tlie 

der  tlie 

level  of  the  sea, 

surface. 

the  .-lir. 

in  Parisian  feet 

Guayaquil      .     . 

260O  c. 

25 -60  C. 

0 

Anserma  nuevo 

23-7 

23-8 

3231 

Zupia   .     .     .     , 

21-5 

21-5 

3770 

Popayan    .     .     , 

18-2 

18-7 

5564 

Quito    .... 

15-5 

15-5 

8969 

The  doubt  about  the  temperature  of  the  earth  within  the 
tropics,  which  1  have  perhaps  myself  contributed  to  raise 
by  my  observations  in  the  Cave  of  Caripe  (Cueva  del  Gua- 
charo),  are  resolved  by  the  consideration  that  I  compared 
the  presumed  mean  temperature  of  the  air  of  the  convent 
of  Caripe  (18  5°),  not  with  the  temperature  of  the  air  of  the 
cavern  (lb-70),  liut  with  the  temperature  of  the  subterra- 
nean stream  (16-80) ;  I  have,  however,  said,  that  it  was 
very  possible  that  mountain  water  from  a  great  height 
might  be  mixed  with  the  water  of  the  cavern  (Relat,  hist, 
t.  iii.  146-194). 

175  (p.  67.) — Boussingault,  in  Annales  de  Chimie,  t.  Iii. 
p.  181.  The  spring  of  Chaudes  Aigues  in  Auvergne,  is  only 
80O  C.  It  is  also  to  be  observed  that,  whilst  the  aguas  ca- 
lientes  de  las  Trincheras  burst  out  from  a  granite  rock, 
split  into  regular  blocks,  and  far  from  all  volcanoes,  and 
have  fully  a  temperature  of  97°  C.,  the  whole  of  the  springs 
that  rise  on  the  Hanks  of  still  active  volcanoes,  Pasto,  Coto- 
paxi,  and  Tunguragua,  only  show  a  temperature  of  from 
360  to  540. 

176  (p.  67.) — The  Cassotis,  or  spring  of  St.  Nicholas,  and 
the  Castalia,  foot  of  the  Phaedriadae  (Pausauias,  x.  24,  25, 
and  X.  8,  9)  ;  the  Pirene,  Aciocorinth  (in  Strabo.  p.  379)  j 
the  Erasinos-spring,  Mount  Chaim,  South  from  Argos  (in 
Herodotus,  vii  67,  and  Pausanias,  ii.  24,  7)  ;  the  spring  of 
Aedepsos,  Cubcea,  some  of  which  have  a  temperature  of  310, 
others  one  of  from  620  to  750  (in  Strabo,  p.  60  and  447, 
Athenseus,  ii.  3,  73)  ;  the  hot  springs  of  Thermopylae,  fool 
of  Oeta,  650  (in  Pausan.  x.  21,  2) ;  all  from  MS.  notices  by 
Professor  Curlius.  the  learned  companion  of  Otfried  Miiller, 

177  (p.  67.)— Plin,  ii.  106:  Seneca,  Epist.  79,  ^  3,  ed. 
Ruhkopf.  (Beaufort,  Survey  of  the  Coast  of  Karamania, 
1820,  Art.  Yanar,  next  Deliktasch,  the  ancient  Phaselis,  p. 
24).  See  also  Ctesias,  Fragm.  cap.  x.  p.  250,  ed.  Bfthr . 
Strabo,  lib.  xiv.  p.  665,  Casauli. 

178  (p.  67.)— Arago,  in  Annuaire  for  1845,  p.  234. 

179  (p.  67.)— Acta  S.  Patricii,  p.  555,  ed.  Ruinart,  t.ii,  p 
385,  Mazochi.  Dureau  de  la  Malle  first  directed  attention 
to  this  remarkable  passage,  in  his  Recherches  sur  la  Topo- 
graphic de  Carthage,  1835,  p.  276,  (Vide  Seneca,  Nat. 
Quaest.  iii.  24.) 

ISO  (p.  68.)— Humboldt,  Rel.  hist.  t.  iii.  p.  562—567 ;  Asie 
centrale,  t.  i.  p.  43,  t.ii.  p.  505— 515;  Vuesdes  Cordiileres, 
pi.  xli.  On  the  Macalubi  (the  Arabic  Makhlub,  cast  down), 
and  how  the  earth  ejected  liquid  earth,  vide  Solinus,  cap. 
V. ;  idem  ager  Agrigenlinus  eruclat  limosas  scaturigines,et 
ut  venae  fontium  suflficiunt  rivis  subministrandis,  ita  in  hao 
Siciliae  parte  solo  nunquam  deficiente,  aeterna  rejectatione 
terram  terra  evoiriit, 

181  (p.  68.)— See  the  interesting  little  map  of  the  island 
Nisyros,  in  Rose,  Reise  auf  den  griechischen  Inseln,  Bd.  ii, 
1843-,  S.  69. 

182  (p.  68.)— Leopold  von  Buch,  Phys,  Beschreibung  der 
Canarischen  Inseln,  S.  326  ;  and  on  Erhebungscratere  und 
Vulcane,  in  Poggend.  Ann.  Bd.  37,  S.  189,  Strabo  distin- 
guishes very  finely  between  the  two  modes  in  which  islands 
are  produced,  when  he  sjieaks  of  the  separation  of  Sicily 
from  Calabria.  ".Some  islands,"  he  says  (lib.  vi.  p.  258,  ed. 
Casaub.),  "are  fragments  of  the  continent;  others  have 
arisen  from  the  sea— an  event  that  still  happens  at  the  pres- 
ent day :  for  the  islands  of  the  great  ocean  have  probably 
been  lifted  from  its  bosom,  those  that  lie  off  promontories 
have  probably  been  detached  from  the  main  land." 

183  (p.  68.) — Ocre  Fisove  (Mons  Vesuvius)  in  the  Umbri- 
an  language,  (Lassen.  Deutung  der  Eugubinischen  Tafeln, 
im  Rhein.  Museum,  1832,  S.  387) ;  the  word  ocre  is  prob- 
ably genuine  Umbrian,  and  means,  as  Festus  informs  us. 
Mountain.  Minn,  if  kiTvti  be,  as  Voss  says,  an  Hellenic 
sound,  and  be  connected  with  aldiii  and  aiQivoi,  may  signify 
a  burning  and  shining  mountain.  But  this  etymological  der- 
ivation seems  doubtful.  The  word  ^Etna  would  probably 
be  found  a  Sicilian  word,  had  we  but  any  remains  of  the 
Sicilian  language.  The  oldest  eruption  of  Etna  spoken  of 
is  that  referred  to  in  Pindar  and  ^schylus  under  Hiero 
(Olymp.  75,  2),  But  it  is  probable  that  Hesiod  was  aware 
of  eruptions  of  the  mountain  before  the  settlement  of  the 


134 


NOTES  TO  PRECEDING  SECTION. 


Greek  Colony.  The  word  klrvrj  in  the  text  of  Hesiod,  is 
of  doubtful  origin,  as  I  have  shown  elsewhere.  (Humboldt, 
Exameu.  crit.  de  la  G6qgr.  t.  i.  p.  168.) 

184  (p.  68.)— Seneca,  Epist.  79. 

185  (p.  68.)— Aelian.  Var.  hist.  viii.  11. 

186  (p.  69.)— Petri  Bembi  Opuscula  (Aetna  Dialogus), 
Basil.  1556,  p.  63  ;  "  Quicquid  in  Aetnae  matris  uterocoale- 
Bcit,  nunquam  exit  ex  cratere  superiore,  quod  vel  eo  ince- 
dere  gravis  materia  non  queat,  vel,  quia  inferius  alia  spira- 
tnenta  sunt,  non  fit  opus.  Despumant  flammis  urgentibus 
ignei  rivi  pigro  fluxa  tolas  delambentes  plagas,  et  in  lapi- 
dem  indurescunt." 

18"  (p.  69.)— See  my  drawing  of  the  volcano  of  Jorullo, 
of  its  Hornitos  and  of  the  uplifted  Malpays,  in  my  Vues  de 
Cordiil^res,  PI.  xliii.  p.  239. 

1*^  (p.  69.) — Humboldt,  Essai  sur  la  G6ogr.  des  plantes 
et  Tableau  phys.  des  Regions  6quinoxiales,  1807,  p.  J30, 
und  Essai  geogn.  sur  le  gisement  des  Roches,  p.  321.  But 
that  the  total  absence  of  streams  of  lava,  along  with  inces- 
sant activity  of  volcanoes,  is  not  connected  solely  with  the 
configuration,  position,  and  absolute  height  of  the  mountains, 
■we  are  assured  by  the  phenomenon  of  the  greater  number 
of  the  volcanoes  of  Java.  (Vide  Leop.  von  Buch,  Descr. 
phys.  des  lies  Canaries,  p.  419  ;  Reinwardt  and  Hoffmann 
m  Poggend.  Ann.  Bd.  xii.  S.  607.) 

I8i)  (p.  70.)— See  the  bases  of  my  measurements  compared 
with  those  of  Saussure  and  Lord  Minto,  in  the  Abhand- 
lungen  der  Acad6mie  der  Wiss.  zu  Berlin  kus  den  J.  1822 
and  1823,  S.  30. 

190  (p.  70.)— Pimelodes  Cyclopum  s.  Humboldt,  Recueil 
^'Observations  de  Zoologie  et  d'Anatomie  compar6e,  t.  i.  p. 
21-25. 

191  (p.  71.) — Leop.  von  Buch,  in  Poggend.  Ann.  Bd.  xxxvii. 
«.  179. 

192  (.  71.) — On  the  chemical  origin  of  iron  glance  in  vol- 
canic masses,  vide  Mitscherlich  in  Poggend.  Ann.  Bd.  xv. 
S.  630  ;  and  on  the  extrication  of  hydrochloric  acid  gas, 
Gay-Lussac  in  the  Annales  de  Chimie  et  de  Phys.  t.  xxii. 
p.  423. 

193  (p.  71.) — See  the  beautiful  experiments  on  the  refri- 
geration of  rocky  masses  in  BischoflTs  Wavmelehre,  S.  384, 
443,  500—512. 

194  (p.  71.) — Berzelius  and  Wohler  in  Poggend.  Annalen, 
Bd.  i.  S.  221,  and  Bd.  xi.  S.  146  ;  Gay-Lussac,  in  the  Annales 
de  Chimie,  t.  xxii.  p.  422;  Bischoff,  Reasons  against  the 
Chemical  Theory  of  Volcanoes,  in  the  English  edition  of  his 
Wftrmelehre,  p.  297—309. 

195  (p.  72.) — According  to  Plato's  geognostic  notions,  as 
they  are  exposed  in  the  Phiedo,  Periphlegethon,  in  respect 
of  the  activity  of  volcanoes,  plays  nearly  the  same  part 
which  we  now  ascribe  to  the  increased  heat  of  the  earth 
with  the  greater  depth,  and  the  melted  state  of  the  internal 
strata  of  the  earth.  (Phaedo,  ed.  Ast.  p.  603  and  607,  An- 
not.  p.  808  and  817.)  "  Within  the  earth,  all  around,  there 
are  greater  and  smaller  caverns.  There  water  flows  in 
abundance  ;  and  also  much  fire,  great  fire-streams,  and 
streams  of  wet  mud  (here  purer,  there  more  filthy)  as  in 
Sicily  the  streams  of  mud  that  are  poured  out  before  and 
along  with  the  fire-stream  itself:  all  places  arc  filled  with 
these,  according  as  each  of  the  streams  takes  its  several 
way.  Periphlegethon  flows  out  into  an  extensive  district 
burning  with  fierce  fire,  where  it  forms  a  lake  larger  than 
our  sea,  boiling  with  water  and  mud.  From  hence  it  moves 
in  circles  round  the  earth  turbid  and  muddy."  This  stream 
of  melted  earth  and  mud  is  so  much  the  general  cause  of 
volcanic  phenomena,  that  Plato  adds :  "  Thus  is  Periphle- 
gethon constituted,  from  which  also  the  fire-streams  (o? 
^vaKcg)  inflate  small  or  detached  portions  wherever  these 
are  met  with  on  the  earth  (ottt]  tiv  rvx^oai  tJjs  y^/j).  Vol- 
canic scoriie  and  lava  streams  are  therefore  portions  of  per- 
iphlegethon itself,  portions  of  the  subterranean  melted  and 
ever-moving  mass.  That  ol  pvaKcg  are  lava  streams,  and 
not,  as  Schneider,  Passow,  and  Schleiermacher,  will  have 
it,  "fire-vomiting  mountains,"  appears  from  many  passages 
that  have  been  already  collected  by  Ukert  (Geogr.  der 
Oriechen  und  Romer,  Th.  ii.  1.  S.  200)  ;  ^va},  is  the  vol- 
canic phenomenon  seized  from  its  most  remarkable  point  of 
view,  the  lava  stream.  Whence  the  expression  the  ^xuikcs 
of  JEtna.  Aristot.  Mirab.  Ausc.  t.  ii.  p.  833,  (>  38,  Bekker  ; 
Thucyd.  iii.  116  ;  Theophr.  de  Lap.  22,  p.  427;  Schneider, 
Diod.  v.  6,  and  xiv.  59,  where  the  remarkable -words  :  ''  many 
places  near  the  sea,  not  far  from  .^tna,  were  destroyed," 
vnb  Tov  kuXovu'evov  pvuKog ;  Strabo,  vi.  p.  269,  xiii.  p,  628, 
and  of  the  celebrated  glowing  mud  of  the  Lelantine  plain  in 
Cubaea  (Strabo,  i.  p.  58,  Casamb.) ;  lastly  Appian.  de  bello 
civili,vi.  114.  The  blame  which  Aristotle  throws  on  the 
geological  fancies  of  the  Phaedo  (Meteor,  ii.  2,  19)  attaches 
only  to  the  rivers  which  flow  over  the  surface  of  the  earth. 
The  expression,  so  distinct  in  reference  to  the  "  eruptions 
of  wet  mud  in  Sicily  preceding  the  gl'>wing  (lava)  streams" 
is  very  remarkable.  Observations  on  JEtna  could  not  have 
led  to  such  language,  unless  torrents  of  ashes  or  pumice 
mixed  with  the  melted  snow  and  water  of  the  cone  during 
ftn  eruption,  were  taken  for  ejected  mud.    It  seems  more 


probable  that  the  vypov  Trtj^ou  iroTaftot  of  Plato,  the  "  moiflt 
mud  streams,"  are  an  obscure  recollection  of  the  mud-vol- 
canoes of  Agrigentum,  which  1  have  already  referred  to 
(Note  89),  which  eject  mud  with  loud  noises.  The  loss  of 
one  among  the  many  lost  writings  of  Theophrastus  :  nco} 
pvaKOs  rov  iv  "ZiKiyt'cf,  of  which  Diogenes  Laertius  (v.  39) 
makes  mention,  is  much  to  be  regretted  in  connection  with 
this  subject. 

19*5  (p.  72.)— Leopold  von  Buch,  Physical.  Beschreib.  der 
Canarischen  Inseln,  S.  326 — 407.  I  doubt  whether  we  can, 
with  the  able  Darwin  (Geological  Observations  on  the  Vol- 
canic Islands,  1844,  p.  127),  regard  Central  volcanoes  in 
general  as  Rank  volcanoes  of  small  compass  developed  ou 
pjirallel  fissures.  Fried.  Hoff^mann  believed  that  he  per- 
ceived in  the  group  of  the  Lipari  islands,  which  he  has  so 
well  described,  and  in  which  two  eruption-fissures  cross 
each  other  near  Panaria,  an  intermediate  member  between 
the  two  principal  modes  in  which  volcanoes  appear,  the 
central,  and  the  rank  or  row-volcanoes  of  Leopold  von  Buch 
(vide  Poggend.  Annal.  26,  p.  81). 

197  (p.  72.) — Humboldt,  Geognost.  Beob.  iiber  die  Vulkane 
des  Ilochlandes  von  Quito,  in  Poggend.  Annalen,  Bd.  xliv. 
S.  194. 

198  (p.  72.)— Seneca,  whilst  he  speaks  very  pointedly  on 
the  problematical  lowering  of  ^Etna,  says,  in  his  79th  let- 
ter: ''Potest  hoc  accidere,  mm  quia  montis  altitudodesedit, 
sed  quia  ignis  evanuit  et  minus  vehemensaclarguseffertur; 
ob  eandem  causam,  fumo  quoque  per  diem  segniore.  Neu- 
trum  autem  incredibile  est,  nee  montem  qui  devoretur  quo- 
tidie  minui,  nee  ignem  non  manere  eundem  ;  quia  non  ipse 
ex  se  est,  sed  in  aliqua  inferna  valle  conceptus  exaestuat  et 
alibi  pascitur :  in  ipso  monte  non  alimentum  habet  sed 
viam."  (Ed.  Ruhkopfiana,  t.  iii.  p.  32.)  The  subterrane- 
ous communications,  "  by  means  of  galleries,"  between  the 
volcanoes  of  Sicily,  Lipari,  Pithecuse  (Ischia),  and  Vesu- 
vius, which  may  be  conjectured  to  have  been  formerly  on 
fire,  are  fully  recognized  by  Strabo,  who  calls  the  whole 
country  "subigneous."     (Lib.  i.  p.  247,  248.) 

199  (p.  72.) — Humboldt,  Essai  polit.  sur  la  Nouv.  Espagne, 
t.  ii.  p.  173—175. 

'JOO  (p.  73.)— On  the  Eruption  of  Methone,  vide  Ovid. 
Metamorphos.  xv.  296—306) : 

"  Est  prope  Pittheam  tumulus  Troezena  sine  ullis 
Arduus  arboribus,  quondam  planiss)ma  campi 
Area,  nunc  tumulus  ;  nam — res  horrenda  relatu — 
Vis  fera  ventorum,  caecis  inclusa  cavernis, 
Exspirare  aliqua  cupiens,  lucta*aque  frustra 
Liberiore  frui  coelo,  cum  carcere  rima 
Nulla  foret  toto  nee  pervia  flatibus  esset, 
Extentam  tumefecit  humum  ;  ceu  spiritus  oris 
Tendere  vesicam  solet,  aut  direpta  bicorni 
Terga  capro.     Tumor  ille  loci  p«rmansit,  et  alti 
Collis  habet  speciem,  longoque  induruit  aevo." 

This  description  of  a  dome-shaped  elevation  of  the  land,  so 
important  in  a  geological  point  of  view,  accords  remarkably 
with  what  Aristotle  says,  (Meteor,  ii.  8, 17—19)  on  the  up- 
liftment  of  an  Erupticm  island.  "  The  quaking  of  the  earth 
does  not  cease  until  the  wind  (avcfioi)  which  occasions  the 
shocks  has  made  its  escape  into  the  crust  of  the  earth.  So 
did  it  happen  lately  at  Heraclea  in  Pontus,  and  formerly 
too  in  Hiera,  one  of  the  jEolian  islands.  In  this  a  portion 
of  the  earth  swelled  up  and  rose  into  the  shape  of  a  hill 
with  loud  noises,  until  the  powerful  lifting  breath  (irvEi'tJia) 
found  a  vent,  and  threw  out  sparks  and  ashes,  which  cov- 
ered the  neighbouring  town  of  the  Liperians,  and  even  ex- 
tended to  several  towns  of  Italy."  In  this  description,  the 
vesicular-like  distension  of  the  crust  of  the  earth  (a  state  in 
which  many  trachytic  mountains  have  remained)  is  very 
well  distinguished  from  the  erupti<m  itself.  Strabo  (lib.  i, 
p.  59,  ed.  Cas.)  likewise  describes  the  phenomenon  of  Me- 
thone :  "  Near  the  town  in  the  Hermionian  bay,  a  flaming 
eruption  took  place  ;  a  fiery  mountaiti  was  thrown  up,  sev- 
en (?)  stadia  high,  inaccessible  during  the  day  from  heat 
and  sulphureous  odours,  but  sweet-smelling  (?)  in  the  night, 
and  so  not  that  the  sea  i)oiled  five  stadia  off,  and  was  turbid 
full  twenty  stadia  out,  and  was  also  filled  full  of  detached 
masses  of  rock."  On  the  present  niineralogical  constitution 
of  the  peninsula  of  Methone,  vide  Fiedler,  Reise  durch 
Griechenland,  Th.  i.  S.  257—263. 

201  (p.  73.) — Leop.  von  Buch,  Physik.  Beschr.  der  Canar. 
Inseln,  S.  356 — 358,  particular'y  the  French  translation  of 
this  excellent  work,  p.  402  ;  also  in  Poggendorff's  Annalen, 
Bd.  xxxvii.  S.  183.  A  submarine  island  was  again  in  the 
most  recent  times  formed  in  the  crater  of  Santorin.  In 
1810  this  island  was  still  15  fathoms  under  the  surface  of 
the  sea;  but  in  1830  (mly  3  or  4  fathoms.  It  rises  steeply 
like  a  great  cone  from  the  bottom  of  the  sea  ;  and  the  per- 
sistence of  the  sul)marine  activity  is  proclaimed  by  the  ad- 
mixture of  sulphuric  acid  vapours  with  the  sea-water,  so 
that  ships  which  are  coppered,  lying  at  anchor  in  the  bay 
t)f  Neo-Kammeiii,as  well  as  at  Wnmiolimni  near  Methana, 
have  their  bottoms  cleansed  and  made  bright  without  fur- 
ther trouble.     (Vide  Virlet  in  Bulletin  de  la  Society  g6olo- 


NOTES  TO  PRECEDING  SECTION. 


125 


triqiie  (le  Franre,  t.  iii.  p.  109,  and  Fiedler,  Reise  durch 
Gnecheiihmd.  Th.  ii.  S.  469  and  5S4.) 

^^  (p.  73.) — Appearances  of  new  islands  near  San  Mi- 
guel, one  of  the  Azores:  11th  June,  1638,  31st  December, 
1719,  ISihJune,  1811. 

-03  (p.  73.)— Prevost.  in  Bulletin  de  la  Soci6t^  j?6olog-ique, 
t.  ii.  p.  34  ;  Friedrich  Hoffmann,  liinterlassene  Werke,  Bd. 
ii.  S.  451—456. 

204  (p.  73.)_«<  Accedunt  ricini  et  perpetui  Aetnae  mentis 
ignes  et  insuiarum  Aeolidum,  veluti  ipsis  undis  alatur  irt- 
cendium  ;  neque  enim  aliter  durare  tot  seculis  tantus  ignis 
potuisset,  nisi  humoris  nutrimentis  aleretur."  (Justin, 
Hist.  Philipp.  iT.  i.)  The  volcanic  theory  with  which  the 
physical  description  of  Sicily  here  begins  is  extremely  in- 
tricate. Deep-lying  beds  of  sulphur  and  rosin,  an  extreme- 
ly thin  crust,  full  of  cavities  and  readily  divided  ;  violent  mo- 
tion of  the  waves  of  the  sea,  which,  as  they  strike  togeth- 
er, draw  down  air  (the  wind)  for  the  maintenance  of  the 
fire  :  such  are  the  elements  of  the  theory  of  Trogus.  As  he 
presents  himself  as  a  physiognomist  in  Pliny  (xi.  52),  we 
may  presume  that  he  did  not  limit  himself  to  history  alone  ; 
but  many  of  his  works  are  lost  to  us.  The  view  according 
to  which  air  was  forced  into  the  interior  of  the  earth,  there 
to  influence  the  volcanic  force,  is  moreover  connected  with 
the  notions  of  the  ancients  on  the  inflience  exerted  by  the 
direction  of  the  wind  upon  the  intensity  of  the  fire  which 
burns  in  ^tna,  in  Hiera  and  Stromboli  (see  the  remarkable 
passage  in  Strabo,  lib.  vi.  p.  275  and  276).  The  mountain- 
ous island  of  Stromboli  (Strongyle)  was  therefore  regarded 
as  the  seat  of  ^olus,  "  the  controller  of  the  winds,"  as  the 
sailors  foretold  the  weather  from  the  violence  of  the  vol- 
canic eruptions  of  Stromboli.  Such  a  connection  between 
the  eruptions  of  a  small  volcano  and  the  state  of  the  barome- 
ter and  the  quarter  of  the  wind  is  still  recognised  {vide  Leop. 
von  Buch,  Descr.  phys.  des  lies  Canaries,  p.  334  ;  Hoffmann 
in  Poggend.  Ann.  Bd.  xxvi.  S.  8) ;  although  it  must  be  allow- 
ed that  all  our  present  knowledge  of  volcanic  phenomena,  and 
the  slight  alterations  in  the  pressure  of  the  air  that  accom- 
pany our  winds,  do  not  enable  us  to  offer  any  satisfactory 
explanation  of  the  fact.  Bembo,  brought  up  as  a  youth  by 
Greek  exiles  in  Sicily,  gives  a  pleasant  narrative  of  his 
wanderings,  and  in  his  "  ^tna  Dialogns"  (middle  of  the 
I6th  century)  advances  the  theory  of  the  penetration  of  sea 
water  to  the  focus  of  the  volcano,  and  of  the  necessity  of 
the  neighbourhood  of  the  sea.  On  ascending  -(Etna  the 
following  question  is  thrown  out:  "  Explana  potius  nobis 
quae  petimus,  ea  incendia  unde  oriantur  et  orta  quomodo 
perdurent?  In  omni  tellure  nuspiam  majores  fistulae  aut 
meatus  arapliores  sunt  quam  in  locis,  quae  vel  mari  vicina 
sunt,  vel  a  mari  protinus  alluuntur :  mare  erodit  ilia  facil- 
lime  pergitque  in  viscera  terrae.  Itaque  cum  in  aliena 
regna  sibi  viam  facial,  ventis  etiam  facit ;  ex  quo  fit,  ut 
loca  quaeque  maritima  maxime  terraemotibus  subjecta  sint, 
parum  mediterranea.  Habes  quum  in  sulfuris  venas  venti 
fureules  inciderint,  unde  incendia  oriantur  Aetnae  tuae. 
Vides,  quae  mare  in  radicibus  habeat,  quae  sulfurea  sit, 
quae  cavernosa,  quae  a  mari  aliquando  perforata  ventos 
admiserit  aestuantes,  per  quos  idouea  flammae  materies  in- 
cenderetur. 

205  (p.  73.)— See  Gay-Lussac,  sur  les  Volcans,  in  den 
Annales  de  Chimie,  t.  xxii.  p.  427;  and  Bischoff,  Warme- 
lehre,  S.  372.  Reactions  of  the  volcanic  hearth  through 
tensive  columns  of  water,  viz.,  when  the  expansive  force  of 
the  vapour  surpasses  the  hydrostatic  pressure,  are  proclaim- 
ed by  the  erupticms  of  smoke  and  aqueous  vapour,  which 
are  observed  at  different  times  in  Lancerote,  Iceland,  and 
the  Kurile  islands  during  eruptions  of  the  neighbouring 
volcanoes. 

2oe  (p.  73.)— Abel-Remusat,  Lettre  a  Mr.  Cordier,  in  the 
Annales  des  Mines,  t.  v.  p.  137. 

207  (p.  73.)— Humboldt,  Asie  centrale,  t.  ii.  p.  30—33, 
38-52.  70—80,  and  426-428.  The  existence  of  active  vol- 
canoes in  Cordofan,  135  miles  from  the  Red  Sea,  has  lately 
been  denied  by  Riippell  (Reise  in  Nubien,  1829). 

208  (p.  74.)— Dufrenoy  et  Elie  de  Beaumont,  Explication 
de  la  Carte  g6ologique  de  la  France,  t.  i.  p.  89. 

•209  (p.  74.)— Sophocl.  Philoctet.  v.  971  and  972.  On  the 
conjectural  epoch  of  the  extinction  of  the  Lemnian  fire  in 
the  time  of  Alexander,  vide  Buttmann  in  Museum  der  Al- 
terthumswissenschaft,  Bd.  i.  1807,  S.  295 ;  Dureau  de  la 
Malle  in  Malte-Brun,  Annales  des  Voyages,  t.  ix.  1809,  p. 
5 ;  Ukert  in  Bertuch,  Geogr.  Ephemeriden,  Bd.  xxxix.  1812J 
S.  361 ;  Rhode,  Res  Lemnicae,  1829,  p.  8,  and  Walter  Uber 
Abnahme  der  vulkan.  Thatigkeit  in  historischen  Zeiten, 
1844,  S.  24.  The  hydrographical  conception  of  Lemnos  by 
Choiseul  makes  it  extremely  probable  that  the  extinct  found- 
ations of  Moschylos,  together  with  the  island  Chryse,  Phil- 
octetes'  desolate  abode  (Otfried  Miiller,  Minyer,  S.  300) 
have  been  long  swallowed  up  by  the  sea.  Reefs  and  shoals 
to  the  North-east  of  Lemnos  still  show  the  spot  where  the 
iEgaan  Sea  possessed  an  active  volcano  like  Jctna,  Vesuvi- 
us, Stromboli,  and  that  of  the  Lipari  isles. 

210  (p.  74.) — Vide  Reinwardt  and  Hoffmann  in  Poggen- 
dorff's  Aunalen,  Bd.  xii.  S.  607 ;  Leop.  von  Buch,  Descr. 


des  lies  Canaries,  p.  424,426.  The  argillaceous  irind  erup- 
tions of  Carguairazo,  when  tae  volcano  crumbled  together 
in  1698,  the  Lodazales  of  Igualata,  and  the  Moya  of  Pelileo, 
are  volcanic  appearances  of  the  same  Jiature  in  the  high- 
lands of  Quito. 

211  (p.  74.)— In  a  profile  of  the  environs  of  Tezcnco,  To- 
toniico,  and  Moran,  (Atlas  g6ographique  et  Physique,  PL 
vii.)  which  I  originally  (1803)  designed  for  a  Pasigrafia 
geognostica  destinada  al  uso  de  los  Jovenes  del  Colegio  de 
Mineria  de  Mexico,  but  which  was  never  published,  I  en- 
titled (1832)  the  Plutonic  and  volcanic  eruptive  rocks  endo' 
genous,  (that  which  is  engendered  in  the  interior,)  the  sedi- 
mentary and  floEtz  rocks  exogenous  (externally  engender- 
ed). Pasigraphically  the  former  were  indicated  by  an  arrow 
directed  upwards,  f  ,  the  latter  by  an  arrow  directed  down- 
wards, I ,  signs  which  had  certain  pictorial  advantages,  and 
permitted  the  nature  of  the  rock  to  be  shown  without  having 
recourse  to  those  very  unpicturesque  and  arbitrarily-shaped 
cones  which  are  generally  seen  in  such  profile  drawings. 
The  titles  endogenous  and  exogenous  were  borrowed  from 
Decandolle,  who  uses  the  former  in  connection  with  raono- 
cotyledonous,  the  latter  with  dicotyledonous  plants.  Bat 
Mohl's  more  careful  vegetable  anatomy  has  shown,  that  in 
the  strict  sense  of  the  words  the  growth  of  monocotyledo- 
nous  vegetables  does  not  proceed  from  within,  nor  that  of 
decotyledonous  plants /row  without.  ( Vide  Link,  Elementa 
philosophiae  botanicae,  t.  i.  1837,  p.  287 ;  Endlicher  und 
linger,  Grundziige  der  Botanik,  1843,  S.  89 ;  and  Jussieu, 
Trait6  de  Botanique,  t.  i.  p.  85.)  What  I  call  endogenous, 
Lyell,  in  his  Principles  of  Geology,  1833,  vol.  iii.  p.  374, 
characterises  by  the  expression  "  netherformed"  or  "  hy- 
pogene  rocks." 

212  (p.  74.)  —  Vide  Leop.  von  Buch  iiber  Dolomit  als 
Gebirgsart,  1823,  S.  36  ;  and  farther,  Ueber  den  Grad 
der  Fliissigkeit,  welchen  man  plutonisohen  Felsarten  bei 
ihrem  Heraustreten  zuschreiben  soil,  wie  iiber  Entstehung 
des  Gneuss  aus  Schiefern  durch  Einwirkung  des  Granits 
und  der  mit  seiner  Erhebung  verbundeneu  Stoffe,  as  well 
as  in  the  Abhandl.  der  Akad.  der  Wissench.  zu  Berlin  aus 
dem  Jahre  1842,  S.  58  und  63,  and  in  the  Jahrb.  fur  wis- 
senschaftliche  Kritik,  1840,  S.  195. 

213  (p.  75.)— Darwin,  Volcanic  Islands,  1844,  p.  49  and 
154. 

214  (p.  75.) — Moreau  de  Jonnes,  Hist.  phys.  des  Antilles, 
t.  i.  p.  136,  138,  and  543  ;  Humboldt,  Relation  historique, 
t.  iii.  p.  367. 

215  (p.  75.)— At  Teguiza  j  Leop.  von  Buch,  Canarische 
Inselna,  S.  301. 

216  (p.  75.)— Vide  above,  p.  4. 

217  (p.  75.)— Bernhard  Cotta,  Geognosie,  1839,  S.  273. 

218  (p.  75.) — Leop.  von  Buch  iiber  Granit  und  Gneuss  in 
den  Abhandl.  der  Berl.  Akad.  aus  dem  J.  1842,  S.  60. 

219  (p.  75.) — In  the  granite  of  the  Kolivan  Lake,  which 
rises  like  walls,  and  is  divided  into  parallel  narrow  ledges, 
felspar  and  albite  predominate,  titanitic  crystals  are  rare. 
Humboldt,  Asie  centrale,  t.  i.  p.  295 ;  Gustav  Rose,  Reise 
nach  dem  Ural,  Bd.  i.  S.  524. 

220  (p.  75.)— Humboldt,  Relation  historique,  t.  ii.  p.  99. 

221  (p,  75.) — See  the  drawing  of  Biri-tau,  which  I  took 
from  the  south,  with  Kirghish  tents  pitched,  in  Rose,  Reise, 
Bd.  i.  S.  584.  On  granite  balls  scaling  off  concentrically, 
vide  Humboldt,  Rel.  hist.  t.  ii.  p.  597  ;  and  Essai  g6ogn 
sur  le  Gisement  des  Roches,  p.  78. 

223  (p.  75.)— Humboldt,  Asie  centrale,  t.  i.  p.  299—311, 
and  the  drawings  in  Rose's  Reise,  Bd.  i.  S.  611,  in  which 
the  curves  of  the  granitic  layers  pointed  out  by  Leop.  von 
Buch  as  characteristic,  are  repeated. 

223  (p.  75.)— This  remarkable  stratification  was  first  de- 
scribed by  Weiss,  in  Karsten's  Archiv  fiir  Bergbau  und 
Hiittenwesen,  Bd.  xvi.  1827,  S.  5. 

224  (p.  76.) — Dufrenoy  et  Elie  de  Beaumont,  G6ologie  da 
la  France,  t.  i.  p.  130. 

223  (p.  76.)— An  important  part  is  played  by  these  sub- 
stratified  diorites  near  Steben,  in  the  Nailaer  Mountain  dis- 
trict, a  country  where  I  was  engaged  in  mining  work  in  the 
last  century,  and  with  which  some  of  the  happiest  associa- 
tions of  my  youth  are  connected.  Vide  Friedr.  Hoffmann 
in  Poggendorff's  Annalen,  Bd.  xvi.  S.  558. 

226  (p.  76.)— In  the  southern  and  Baschkir-Ural ;  vide 
Rose,  Reise,  Bd.  ii.  S.  171. 

227  (p.  76.)— G.  Rose,  Reise  nach  dem  Ural,  Bd.  ii.  S. 
47 — 52.  On  the  identity  of  Elaeolite  and  Nepheline  (in  the 
latter  the  quantity  of  lime  is  somewhat  larger),  vide  Schee- 
rer,  in  Poggend.  Annalen,  Bd.  xlix.  S.  359-381. 

228  (p.  77.) — See  the  admirable  papers  of  Mitscherlich,  in 
the  Abhandlungen  der  Berl.  Akad.  for  the  years  1822  and 
1823,  S.  25—41  ;  in  Poggendorff's  Annalen,  Bd.  i.  S.  137— 
152,  Bd.  xi.  S.  323—332,  Bd.  xli.  S.  213—216  (Gustav  Rose 
iiber  Bildung  des  Kalkspaths  und  Aragonits  in  Poggend, 
Ann.  Bd.  xlii.  S.  353—366  ;  Haidinger,  in  the  Transactions 
of  the  Royal  Society  of  Edinbu^rgh,  1827,  p.  148). 

239  (p.  77.)— Lyell,  Principles  of  Geology,  vol.  iii.  p.  353 
and  359. 
330  (p.  78.)— The  statements  here  made  of  the  reJationt 


126 


NOTES  TO  PRECEDING  SECTION. 


of  granife  in  reference  to  stratification,  express  the  general 
or  principal  cliaracter  of  the  whole  formation.  In  some 
places  (vide  p.  75,  and  the  description  of  the  Narym  chain, 
hear  the  boundary  of  China,  Rose's  Reise,  Bd.  1.  S.  599) 
granite  indeed  shows  confijjuralions  which  lead  us  to  con- 
jecture that  at  the  period  of  its  eruption  it  was  not  always 
without  fluidity,  just  as  happens  in  the  case  of  Trachyte 
(Dufrenoy  et  Elie  de  Beaumont,  Description  g6ologique  de 
la  France  t.  i.  p.  70).  As  we  have  in  the  text  mentioned 
Ihe  narrow  fissures  through  which  basalt  has  generally  flow- 
ed, I  take  the  opportunity  in  this  place  of  referring  to  the 
wide  chasms  which  have  served  the  melaphyrcs  (which 
must  not  be  confounded  with  the  -basalts)  as  channels  of  ef- 
flux. See  the  interesting  account  by  Murchison,  in  his  Si- 
lurian System,  p.  126,  of  a  chasm  450  feet  wide,  in  the  coal- 
pit at  Cornbrook,  Hoar-Edge,  through  which  the  melaphyre 
has  made  its  way. 

231  (p.  78.)— Sir  James  Hall,  in  the  Edinb.  Transact,  vol. 
V.  p.  43,  vol.  vi.  p.  71  ;  Gregory  Watt,  in  the  Philos.  Trans- 
actions of  the  Royal  Society  of  London,  for  1804,  pt.  ii.  p. 
279  ;  Dartigues  and  Fleuriau  de  Bellevue,  in  the  Journ.  de 
Phys  t.  Ix.'p.  456  ;  Bischoff,  Warmelehre,  S.  313  and  443. 

232  (p.  78.) — Gustav  Rose,  in  PoggeudorfTs  Annalen  der 
Physik,  Bd.  xlii.  S.  364. 

233  (p.  78.) — On  the  dimorphism  of  sulphur,  vide  Mitscher- 
lich,  Lehrbuch  der  Chimie,  ^  55 — 63. 

234  (p.  78.)— On  gypsum  as  monuaxal  crystal,  sulphate  of 
magnesia,  oxides  of  zinc  and  nickel,  vide  Mitscherlich,  in 
Poggend.  Ann.  Bd.  xi.  S.  328. 

235  (p.  78.)—  Coste,  Versuche,  in  Creusot  iiber  das  briichig 
werden  des  Stabeisens,  in  Elie  de  Beaumont,  M6m.  geol.  t. 
ii.  p.  411. 

236  (p.  78.) — Mitscherlich  iiber  die  Ausdehnungder  krys- 
tallisirten  Korper  durch  die  Warme.  in  Poggend.  Ann.  Bd. 
3t.  S.  151. 

237  (p.  78.)— On  double  stratification  cleavage,  vide  Elie 
de  Beaumont,  Geologic  de  la  France,  p.  41  ;  Credner,  Ge- 
ognosie  Thuringens  und  des  Harzes,  S.  40  ;  Riimer,  das 
Rheinische  Uebergangsgebirge,  1844,  S.  5  und  9. 

238  (p.  78.)— With  addition  of  clay,  lime,  and  potash,  not 
silicic  acid  si mplv  coloured  with  oxide  of  iron  ;  Rose,  Reise, 
Bd.  li.  S.  16»,  187,  and  192:  vidt  also  Bd.  i.  S.  427,  whfere 
the  porphyry  balls  are  represented  between  which  the  jas- 
per occurs  in  the  calcareous  gray  wacke  mountains  of  Bo- 
goslowsk,  also  as  a  consequence  of  the  Plutonic  effects  of 
Augitic  rock :  Rose,  Bd.  ii.  S.  545  ;  also  Humboldt,  Asie 
centrale,  t.  i.  p.  486. 

2:J9  (p.  78.)— Rose,  Reise,  nach  dem  Ural,  Bd.  i.  S.  586— 
688. 

210  (p.  78.)— For  the  volcanic  origin  of  mica,  it  is  impor- 
tant to  remember  that  crystals  of  mica  occur  in  the  basalt 
of  the  Bohemian  Middle  Mountains  ;  in  the  lava  of  Vesuvius 
of  1822  (Monticelli,  Sioria  del  Vesuvio  negli  anni  1821  e 
1S22,  t)  99) ;  in  clay-slate  fragments  of  Hohenfels,  not  far 
from  Gerolstein  in  the  Eifel,  enveloped  in  scoriaceous  ba- 
salt, vide  Mitscherlich,  in  Leonhard,  Basalt-Gebilde,  S.  244. 
On  the  pri^duction  of  felspar  in  clay  slate,  through  the  con- 
tact of  porphyry  between  Urval  and  Poiet  (Forez),  vide  Du- 
frenoy, in  G6ol.  de  la  France,  t.  i.  p.  137.  A  similar  con- 
tact gives  the  slate  at  Paiiiipol,  in  Brittany,  an  amygdaloidal 
and  cellular  character,  an  api)earance  which  amazed-  me 
very  much  on  a  geological  journey  which  I  made  on  foot,  in 
company  with  Prof.  Kunth,  through  that  interesting  countiy. 

2-41  (p.  78.)— Leopold  von  Buch  in  the  Abhandlungen  der 
Akad.  der  Wissensch.  zu  Berlin  aus  dem  J.  1842,  S.  63; 
and  in  the  Jahrbiicher  fiir  wisseiischaftliche  Kritik,  Jahrg. 
1840,  S.  196. 

242  (p.  78.) — Elie  de  Beaumont,  in  the  Annales  des  Sci- 
ences naturelles,  t.  xv.  p.  362 — 372  :  *'  En  se  rapprochant 
des  masses  primitives  du  Mont  Rose  etdes  niontagncs  siiu- 
fees  A  I'ouest  de  Coni,  on  volt  les  couches  secondairesperdre 
de  plus  les  caract^res  inh6ients  dleur  mode  de  dep6t.  Sou- 
vent  alors  elles  en  prennent  qui  semblent  provenir  d'une 
toute  autre  cause,  sans  perdre  pour  cela  leur  stratification, 
rappelant  par  cette  disposition  la  structure  physique  d'un 
tison  i  moiti6  charbcmn^  dans  lequel  on  peut  suivre  les  tra- 
ces des  fibres  ligneuses,  bien  au-dela  des  points  qui  present- 
ent  encore  les  caracte res  mutuels  du  bois."  Ft<ie  also  An- 
uales  des  Sciences  naturelles.  t.  xiv.  p.  118-  122;  and  II. 
von  Dechen,  Geognosie,  S.  553.  Among  the  most  remark- 
able evidences  of  the  transformation  of  rocks  under  the  in- 
fluence of  Plutonic  agency,  are  the  belemnitcs  in  the  schists 
of  Nuffenen  (Alpine  valley  of  Egine  and  the  Gries-glacier), 
as  well  as  the  belemnites  in  the  so-called  primitive  limestone, 
which  M.  de  Charpentier  discovered  on  the  western  flank 
of  the  Col  de  Seigne,  between  Enclove  de  Monjovet  and  the 
Alpine-hut  de  la  Lanchette  (Ann.  de  Chimie,  t.  xxiii.  p. 
262),  and  which  he  showed  me  in  Bex,  in  the  autumn  of 
1822. 

243  (p.  78.)— Hoffmann,  in  Poggend.  Annalen,  Bd.  xvi.  S. 
552.  "  Strata  of  the  transition  clay  slate  of  the  Fichtelge- 
birge,  which  can  be  followed  for  four  miles,  and  only  at  ei- 
ther extremity,  where  they  come  into  contact  with  the  gran- 
ate  converted  into  gneiss.    There  we  can  trace  the  gradual 


formation  of  gneiss,  and  the  internal  development  o'  mics 
and  of  felspar  amygaloids  in  clay  slate,  which  indeed  con- 
tains almost  all  the  elements  of  those  substances." 

244  (p.  78.)— In  the  works  of  the  ancient  Greeks  and  Ro- 
mans that  have  come  down  to  us  we  observe  the  want  of 
jasper  columns  and  large  vessels  of  jasper,  a  substance  which 
the  Ural  mountains  almost  exclusively  yield  in  masses  of 
any  magnitude.  The  stone  that  is  worked  as  jasper  in  the 
Altai  (Ravennaja  Sopka,  the  Rhubarb  mountains)  is  a  mag- 
nificent striped  porphyry.  Theophrastus  and  Pliny  reckon 
jasper  among  the  number  of  non-irai}sparent  gems  ;  and  the 
latter  thinks  it  incumbent  on  him  to  mention  a  piece  of  the 
mineral  eleven  inches  long  which  he  had  seen  :  "  Magnitu- 
dinem  jaspidis  undecim  unciarum  vidimus,  formalainque 
inde  effigiem  Neronis  thoracatam."  The  st(me  which  The- 
ophrastus calls  smaragd  or  emerald,  and  from  which  the 
great  obelisks  were  hewn,  he  regards  as  an  unripe  iasper. 

245  (p.  78.)— Iluinholdt,  Lettre  a  M.  Brochant  de  Villiers, 
in  the  Annales  de  Chimie  et  de  Physique,  t.  xxiii.  p.  261  ; 
Leop.  von  Buch,  Geogn.  Briefe  iiber  das  siidliche  Tyrol,  S. 
101.  105,  and  273. 

246  (p.  79  )— On  the  transformation  of  compact  into  gran- 
ular limestone  through  contact  with  granite  in  the  Pyrenees 
(Montague  de  Rancie),  vide  Dufr6noy,  in  the  M^moires  g6- 
ologiques,  t.  ii.  p.  440;  and  in  the  Montagues  de  I'Oisans, 
vide  Elie  de  Beaumont,  Mem.  geol.  t.  ii.  p.  379— 415  ;  by 
Dioritic  and  Pyrorexic  Porjjhyries  (Ophite  ;  Elie  de  Beau- 
mont, G6ol.  de  la  France,  t.  i.  p.  72),  between  Toulouse  and 
St.  Sebastian,  vide  Dufr6noy,  in  M6m.  g^ol.  t.  ii.  p.  130; 
through  Syenite,  in  the  island  of  Elba,  in  which  petrefac- 
tions  still  continue  visible  in  the  limesKme,  in  spite  of  the 
changes  it  has  suffered,  M.  von  Dechen,  Geognobie,  S.  573. 
In  the  metamorphosis  of  chalk,  through  contact  with  basalt, 
the  dislocation  of  the  minute  particles  through  the  produc- 
tion of  crystals  and  the  granulation  is  the  more  remarkable, 
since  we  have  been  made  aware,  by  Ehrenberg's  discover- 
ies, of  the  fact,  that  these  chalk  particles  previously  consist- 
ed of  articulated  rings  (vide  Poggendorff's  Annal.  Bd.  xxxix. 
S.  105  ;  and  on  the  rings  of  Aragonite  precipitated  from  a 
state  of  solution,  Gustav  Rose,  ib.  Bd.  xlii.  S.  354). 

247  (p.  79  ) — Beds  of  granular  limestone  in  granite  at 
Port  d'Or  and  Mont  de  Labourd,  vide  Charpentier,  Consti- 
tution giologique  des  Pyrenees,  p.  144,  146. 

248  (p.  79.) — Leop.  vcm  Buch,  Descr.  des  Canaries,  p. 
394  ;  Fielder.  Reise  durch  das  Ktinigreich  Griechenlind, 
Th.  ii.  S.  181,  190,  and  516. 

249  (p.  79.)— I  have  already  referred  to  the  remarkable 
passage  in  Origen's  Philosophumena,  cap.  14  (Opera  ed. 
Delarue,  t.  i.  p.  893).  From  the  whole  context  it  is  not  very 
unlikely  that  Xenophanes  meant  "  an  impression  of  laurel," 
(rvtroT]  6d(pvy]i,)  not  an  "  impression  of  a  fish,"  (tvi:ov  acpvrjs). 
Delarue  blames  Gronovius  unfairly,  who  made  the  correc- 
tion that  "  turned  the  laurel  into  an  anchovy."  The  petri- 
fied fish  is  a  far  more  likely  object  than  the  natural  image 
of  Silenus,  which  the  quarry-men  insisted  they  had  dug 
out  of  the  marble  quarries  of  Paros  (the  mountain  Mar- 
pessos,  Servius  ad  Virgil,  ^u.  vi.  471),  Plin.  xxxvi.  5. 

250  (p.  79.)_On  the  geological  relations  of  the  town  of 
Carrara  Luna,  Selene  civitas,  vide  Strabo,  lib.  v.  p.  222; 
Savi,  Osservazioni  sui  terreni  jmtichi  Toscani,  in  the  Nuovo 
Giornale  de'  Lettcrati  di  Pisa,  No.  63;  and  Hoffmann,  in 
Karsten's  Archiv  fiir  Mineralogic,  Bd.  vi.  S.  258-263,  as 
also  his  Geogn.  Reise  durch  Itaiien,  S.  244—265. 

251  (p.  79.)— According  to  the  view  of  an  excellent  and 
experienced  observer,  Karl  von  Leonhard  ;  see  his  Jahrbuch 
fiir  Mineralogie,  1834,  S.  329,  and  Bernhard  Cotta,  Geog- 
nosie, S.  310. 

252  (p.  79.)— Leop.  von  Buch,  Geognostische  Briefe  an 
Alex,  von  Humboldt,  1824,  S.  36  and  82  ;  also  in  the  Annales 
de  Chimie,  t.  xxiii.  p.  276,  and  the  Abhandl.  der  Berliner 
Akad.  aus  den  J.  1822  und  1823,  S.  83—136  ;  H.  von  Dechen, 
Geognosie,  S.  574 — 576. 

253  (p.  79.)— Hoflfmann,  Geogn.  Reise  bearbeitet  von  H. 
von  Dechen,  S.  113-119,  380—386;  Poggend.  Ann.  der 
Physik,  Bd.  x.xvi.  S.  41. 

254  (p.  80.) — Dufr6noy,  inM6moircs  g6ologiqnes,  t.ii.  p 
145  and  179. 

255  (p.  80.) — Humboldt,  Essai  g6ogn.  sur  le  Gisement  de» 
Roches,  p.  93  ;  Asie  centrale,  t.  iii.  p.  532. 

256  (p.  80.) — Elie  de  Beaumont,  in  Annales  des  Sciences 
naturelles,  t.  xv.  p.  362  ;  Murchison,  Silurian  System,  p.  266. 

257  (p.  80.)— Rose,  Reise  nach  dem  Ural,  Bd.  i.  S.  364  and 
367. 

258  (p.  80.)— Leop.  von  Buch,  Briefe,  S.  109—129.  Vide 
also  Elie  de  Beaumont  on  the  Contact  of  Granite  with  Ju- 
rastrata,  in  Mem.  g6ol.  t.  ii.  p.  408. 

259  (p.  80.)— Hoffmann,  Reise,  S.  30  and  37. 

260  (p.  80.)— On  the  chemical  process  in  the  formation  of 
iron  glance,  vtrfe  Gay-Lussac  in  Annales  de  Chimie,  t.  xxii. 
p.  415  ;  and  Mitscherlich  in  Poggend.  Ann.  Bd.  xv.  S.  630. 
In  the  cavities  of  the  Obsidian  of  the  Cerro  del  Jacal,  which 
I  brought  with  me  from  Mexico,  crystals  of  olivine  have 
also  been  formed  (apparently  deposited  from  vapour,  vide 
Gustav  Rose,  in  Poggend.  Ann.  Bd.  x.  S.  323).    Olivine 


NOTES  TO  PRECEDING  SECTION. 


127 


therefore  occurs  :  in  basalt,  in  lava,  in  obsidian,  in  artificial 
Bcoriae,  in  meteoric  stones,  in  the  syenite  of  Elfdale,  and  (as 
hyalosidcrite)  in  the  Wacke  of  Kaiserstuhle. 

2fii  (p.  60.)— Constantin  von  Beust  liber  die  Porphyrge- 
bilde,  1635,  S.  89—96  ;  his  Beleuchtung  der  Werner'achen 
Gangtheorie,  1840,  S.  6  ;  C,  von  Weissenbach,  Abbildungen 
merkwurdigrer  Gangverhftltnisse,  1836,  fig.  12.  The  band- 
like structure  of  the  veins  is  however  as  little  general,  as  is 
the  sequence  in  respect  of  age  of  the  several  members  of 
these  masses.  Vide  Frieslebeu  iiber  die  sflchsischen  Erz- 
gttnge,  1843,  S.  10—12. 

2W  (p.  80.)— Mitscherlich  Ober  die  kiinstlicheDarstellung 
der  Mineralicn,  in  the  Abhandlungen  der  Akademie  der 
Wiss.  zu  Berlin  aus  den  Jahren  1822  und  1823,  S.  25—4!. 

*o  (p.  80.)— In  scoriie:  crystals  of  felspar  discovered  by 
Heine,  after  the  extinction  of  a  roasting  copper  ore  furnace, 
not  far  from  Sangerhausen,  analysed  by  Kersten  (Poggend. 
Annalcn,  Bd.  xxxiii.  S.  337);  of  augite  in  the  scoriie  of 
Sable  (Mitscherlich  in  den  Abhandl.  der  Akad.  zu  Ber- 
lin, 1822  and  1823,  S.  40) ;  of  Olivine  (SefstrSm  in  Leon- 
hard,  Basalt-Gebilde,  Bd.  ii.  S.  495)  ;  of  Mica  in  old  scoria; 
of  Schloss  Garpenberg  (Mitscherlich  in  Leonhard,  loc.  cit. 
S.  506)  ;  of  magnetic  iron  in  scoriie  of  Chatillon  sur  Seine 
(Leonhard,  S.  441) ;  of  iron-glance  arising  in  potter's  clay 
(Mitscherlich  in  Leonhard,  S.  234). 

stj*  (p.  80.) — Produced  on  purpose  :  Idokras  and  garnet 
(Mitscherlich  in  Poggendorff's  Annalen  der  Physik,  Bd. 
xxxiii.  S..340)  ;  ruby  (Gaudin  in  Comptes  rendus  de  I'Acad- 
6mie  des  Sciences,  t.  iv.  pt.  iv.  p.  999) ;  olivine  and  augite 
(Mitscherlich  and  Berthier,  in  Annales  de  Chiniie  et  de 
Physique,  t.  24,  p.  376).  Although,  according  to  Gust. 
Rose,  augite  and  hornblende  show  the  greatest  similarity 
in  the  form  of  their  crystals,  and  their  chemical  composition 
is  almost  identical,  still  hornblende  has  never  been  found 
by  the  side  of  augite  in  scoriae  :  even  as  little  have  chemists 
succeeded  in  their  attempts  at  producing  hornblende  or  fel- 
spar (Mitscherlich  in  Poggend.  Annalen,  Bd.  xxxiii.  S.  340, 
and  Rose,  Reise  nach  dem  Ural,  Bd.  ii.  S.  358  and  363). 
See  also  Beudant,  in  Mem.  de  I'Acad.  des  Sciences,  t.  viii. 
p.  221,  and  Becquerel's  able  inquiries,  in  his  Trait6  ed 
l'Electricit6,  t.  i.  p.  334  ;  t.  iii.p.  218;  t.  v.  l,p.  148  and  185. 

2t)5  (p.  80.)— D'Aubuisson,  in  Journal  de  Physique,  t. 
kviii.  p.  128. 

266  (p.  81.)— Leop.  von  Buch,  Geognost.  Briefe,  S.  75— 
82  ;  where  it  is  at  the  same  time  shown,  that  the  red  sand- 
stone (the  dead  layer  of  the  Thuringian  floetz  formations) 
and  the  coal  formation  must  be  viewed  as  products  of  erup- 
tive porphyritic  rocks. 

267  (p.  81.) — On  Hooke's  "hope  to  raise  a  chronology" 
out  of  the  study  of  fossil  shells,  and  Ui  state  the  intervals  of 
the  time  wherein  such  or  such  catastrophes  or  mutations 
have  happened,  vide  Posth.  Works,  Lecture,  Feb.  29, 1688. 

267*  (p.  81.)— A  discovery  of  Miss  Mary  Anuing,  who  also 
first  discovered  the  coprolites  of  fishes.  These,  and  the  ex- 
crements of  the  Ichthyosaurus,  have  been  found  in  such 
quantities  at  Lyme  Regis,  that  they  seem  to  lie,  according 
to  Buckland's  expression,  "  heaped  like  potatoes  upon  the 
ground."  Vide  his  Geology  with  reference  to  Natural  The- 
olo?y,  vol.  i.  p.  188-202,  and  305. 

2C>J  (p.  81.) — Leop.  von  Buch,  in  Abhandlungen  der  Akad. 
der  Wiss.  zu  Berlin  aus  dem  J.  1837,  S.  64. 

269  (p.  82.) — The  same,  Gebirgsformationen  von  Russland, 
1840,  S.  24-40. 

2"0  (p.  82.) — Agassiz,  Monographic  des  Poissons  fossiles 
du  Vieux  Gres  Rouge,  p.  vi.  and  4. 

271  (p.  82.)— Leop.  von  Buch  in  Abhandl.  der  Berl.  Akad. 
1838,  S.  149—168  ;  Beyrich,  Beitr.  zur  Kenntniss  des  Rhein- 
ischen  Uebergangsgebirges,  1837,  S.  45. 

2*2  (p.  82.) — Agassiz,  Recherches  sur  les  Poissons  fos- 
siles, t.  i.  Introd.  p.  xviii.  (Davy,  Consolations  in  Travel, 
Dial,  iii.) 

273  (p.  82.) — According  to  Hermann  von  Meyer,  a  pro- 
tosaurus  (Paljpologica,  S.  229).  The  rib  of  a  saurian,  said 
to  be  from  the  mountain  limestone  of  Northumberland,  is, 
according  to  Lyell,  extremely  doubtful  (Geology,  vol.  i.  p. 
148).  The  discoverer  himself  asoribes  it  to  alluvial  strata 
which  cover  the  limestone. 

274  (p.  82.)— F.  von  Alberti.  Monographie  des  Bunten 
Sandsteins,  Muschelkalks  und  Keupers,  1834,8. 119  und  314. 

27.5  (p.  82.) — See  the  acute  considerations  of  H.  von  Meyer 
(Palrcologica,  S.  228—252)  on  the  organization  of  the  flying 
reptiles.  In  the  petrified  specimen  of  Pterodactylus  cras- 
sirostris,  which,  as  well  as  the  longer  known  Pterod.  lon- 
girostris,  was  found  in  the  lithographic  limestone  of  Solen- 
hofen.  Professor  Goldfuss  has  found  *'  traces  of  the  mem- 
brane which  served  for  flight,"  as  well  as  "  impressions  of 
the  curled,  flocky,  in  some  places  inch-long  hair,  which  cov- 
ered the  skin." 

276  (p.  82.)— Cuvier,  Recherches  sur  les  Ossemens  fos- 
siles, t.  i.  p.  Iii. — Ivii.  See  also  the  geological  scale  of 
epochs  in  Phillips's  Geology,  1837,  p.  166-185. 

277  (p.  82.)— Agassiz,  Poissons  fossiles,  torn.  i.  pt.  xxx. 
and  torn.  iii.  p.  1—52;  Buckland,  Geology,  vol,  i.  p.  273 
—277. 


278  (p,  83.)— Ehrcnberg,  iiber  noch  jetzt  khendc  Thier- 
arten  der  Krpidei)ildung  in  den  Abhandl.  der  Berliner  Akad. 
aus  dom  J.  1639,  S.  164. 

279  (p.  63.) — Valenciennes,  in  Comptes  rendus  de  I'Acad. 
des  Sciences,  torn.  vii.  18.38,  j)t.  ii.  p.  580. 

^280  (p.  83.)— The  Weald-Clay  ;  Beudant,  G^ologie,  p. 
173.  The  ornitholites  increase  in  number  in  the  gypsum  of 
the  tertiary  formation  {Cuvier,  Ossemens  fossiles,  u>iu.  iii. 
p.  302—328). 

281  (p.  83.)— Leop.  von  Buch,  iu  Abhandl.  der  Berl.  Akad. 
aus  dem  J.  1830,  S.  135-167. 

282  (p.  83.)— Quenstedt,  Flozgebirge  Wurtemberga,  1843, 

283  (p.  83.)— Ibid.  S,  13. 

284  (p.  83.)— Murchison  divides  the  variegated  sandstone 
into  two  divisions,  the  upper  of  which  remains  the  Trias  of 
Alberti,  whilst  out  of  the  lower,  to  which  the  Voges-sand- 
stone  of  Elie  de  Beaumont  belongs,  the  Zechsteiii  and  the 
Todtliegendes,  he  forms  his  Permian  System.  With  the 
upper  trias,  i.  e.,  with  the  upper  division  of  our  variegated 
sandstone,  he  begins  the  secondary  formations ;  the  Per- 
mian system,  the  mountain  or  carboniferous  limestone,  the 
Devonian  and  Silurian  strata,  are  with  him  paleozoic  for- 
mations. According  to  these  views,  chalk  and  jura  are 
called  the  upper,  keuper,  muschelkalk,  and  variegated  sand- 
stone, the  inferior  secondary  formations  ;  the  Permian  sys- 
tem and  the  carboniferous  lime  are  entitled  the  upper,  the 
devonian  and  silurian  strata  together  the  inferior  palseozoic 
formations.  The  basis  of  this  general  classification  is  de- 
veloped in  the  great  work  in  which  the  unwearied  British 
geologist  gives  an  account  of  a  great  portion  of  the  east  of 
Europe. 

280  (p.  83.)— Cuvier,  Ossemens  fossiles,  1821.  torn.  i.  p. 
157,  262,  and  264.  Vide  Humboldt,  iiber  die  Hochebene 
von  Bogota  in  der  Deutchen  Bierteljahrs-Schrift,  1839,  Bd. 
i.  S.  117. 

286  (p.  83.)— Journal  of  the  Asiatic  Society,  No.  xv.  p.  109. 

287  (p.  84.) — Bevrich,  in  Karsten's  Archiv  fiir  Mineral- 
ogie,  1844,  Bd.  xviii.  S.  218. 

288  (p.  84.) — Through  the  admirable  labours  of  Count 
Sternberg,  Adolph  Brongniart,  Goppert,  and  Lindley. 

28i»  (p.  84.)  — Vtde  Robert  Brown's  Botany  of  Consro,  p. 
42,  and  the  unfortunate  d'Urville,  in  the  Memoir:  De  la 
distribution  des  Fougeres  sur  la  surface  du  globe  terrestre. 

2^  (p.  81.)— To  this  belong  the  Cycadeie  of  the  old  coal 
formation  of  Radnitz,  Bohemia,  discovered  by  Count  Stern- 
berg, and  described  l)y  Corda.  Two  species,  Cycadites  et 
Zamites  Coniai,  vide  Goppert,  fossile  Cycadeen  in  den  Ar- 
beiten  der  Schles.  Gesellschaft,  fur  valerl.  Cultur  im  J 
1843,  S.  33,  40,  and  50.  In  the  coal  formation  of  Koniga- 
hiitte.  Upper  Silesia,  a  Cycadea  (Pterophyllum  gonorrha- 
chis,  Goep.)  has  also  been  found. 

291  (p.  84.) -Lindley,  Fossil  Flora,  No.  xv.  p.  16.^.^ 

292  (p.  84.)— Fossil  Coniferae,  in  Buckland,  Geology,  p. 
483—490.  Mr.  VVitham  has  the  merit  of  having  first  de- 
tected the  existence  of  coniferse  in  the  earlier  vegetation  of 
the  old  coal  formatifms.  All  the  stems  of  trees  discovered 
in  these  formations  had  previously  been  regarded  as  pulms. 
The  species  of  the  genus  Araucarit.es,  however,  is  not  pe- 
culiar to  the  coal  fields  of  Great  Britain  ;  they  are  also  met 
with  in  Upper  Silesia. 

293  (p.  84.)  —  Adolph  Brongniart,  Prodrome  d'une  Hi.st. 
des  Vegetaux  fossiles,  p.  176;  Buckland,  Geology,  p.  479; 
Endlicher  and  Unger,  Grundziige  der  Botanik,  1843,  S.455. 

294  (p.  84.) — "  By  means  of  Lepidodendron  a  better  pas- 
sage is  established  from  Flowering  to  Flowerle.ss  Plants 
than  by  either  Equisetum  or  Cyras,  or  any  other  known 
genus." — Lindley  and  Huiton,  Fossil  Flora,  vol.  ii.  p.  53. 

29t  (p.  84.) — Kunth,  Anordung  der  Pflanzenfamilien,  in 
his  Handb.  der  Botanik,  S.  307  and  314. 

296  (p.  84.)— That  fossil  coal  consists  of  vegetable  fibres 
carbonized  not  through  fire,  but  in  the  moist  way,  and  un- 
der the  co-agency  of  sulphuric  acid,  is  vouched  for  particu- 
larly by  Goppert's  able  observations,  of  a  piece  of  Amber- 
tree  wood  converted  into  coal  (vide  Karsten,  Archiv  fffr 
Mineralogie,  Bd.  xviii.  S.  530).  The  coal  lies  close  to  the 
wholly  unaltered  amber.  On  the  part  which  the  lower 
vegetables  may  have  had  in  the  production  of  coal,  vide 
Link  in  the  Abhandl.  der  Beriiuer  Akademie  der  Wissen- 
schaften,  1838,  S.  38. 

297  (p.  84.) — See  the  excellent  paper  of  Chevandier,  in 
the  Comptes  rendus  de  I'Acad.  des  Sciences.  1844,  torn. 
xviii.  pt.  I.  p.  285.  In  order  to  compare  the  half-inch  thick 
layer  of  carbonaceous  matter  with  the  coal  strata,  regard 
must  also  be  had  to  the  enormous  pressure  which  these 
strata  have  suflfered  from  the  superincumbent  beds,  and 
which  is  even  attested  by  the  generally  flattened  form  of 
the  fossil  stems  of  trees  that  are  dug  up.  "  The  wood-hills, 
as  they  are  called,  of  the  southern  shore  of  the  island  of 
New  Siberia,  discovered  in  1806  by  Sirowatskoi,  consist, 
according  to  Hedenstrom,  of  elevations  of  about  30  fathoms, 
made  up  of  horizontal  layers  of  sandstone  interchangingly 
with  bituminous  trunks  of  trees.  On  the  tops  of  the  hil- 
locks the  stems  stand  erect.    The  stratum  of  drift  wood  is 


138 


NOTES  TO  PRECEDING  SECTION. 


visible  for  five  wersts."  Vide  Wrangel,  Reise  Iftngs  der 
Nonlkuste  von  Siberien  in  den  Jahren  1220—1824,  Th,  i. 
S.  202. 

298  (p.  84.) — This  corypha  is  the  sopato  (zoyatl,  Aztekian) 
or  paima  dulce  of  the  natives  ;  vide  Humboldt  and  Bon- 
plfiud,  Synopsis  Plant,  ^quihoct.  Orbis  Nwvi,  torn.  i.  p.  302. 
One  deeply  versed  in  the  American  langnag^es,  Professor 
Buschmann,  observes  that  the  palma  soyate  is  also  named 
in  Vepe's  Vocabulario  de  la  Leng-ua  Othomi,  and  that  the 
Aztekian  word  zoyatl  (Molina,  Vocabulario)  also  occurs  in 
the  local  names  zoyat.itlan  and  zoyapanco  near  Chiapa. 

2!*^  (p.  85.)— Near  Baracoa  and'  Cayos  de  Moa  ;  vide  Ta- 
gcbuch  des  Admirals  vom  25  and  27  November,  1492,  and 
Humboldt,  Examen  critique  de  I'llist.  de  la  Geogr.  du  Nou- 
Teau  Continent,  tom.  ii.  p.  252,  and  torn.  iii.  p.  23.  Colum- 
i)us  was  so  observant  of  all  natural  objects,  that  he  distin- 
guished— and  was,  indeed,  the  first  to  do  so — Podocarpus 
from  Pinus.  "I  find,"  he  says,  "en  la  ticrra  aspera  del 
Cibao  pinos  que  no  Uevan  pinas  [fir-tops  or  cones],  pero  por 
tal  orden  compuestos  por  naturaleza,  que  (los  frutos)  pare- 
ceu  azeytunas  del  Axarafe  de  Sevilla."  The  great  botanist, 
Richard,  when  he  produced  his  excellent  work  on  the  Cy- 
ciideie  and  Coniferse,  was  not  aware  that  long-  before  L'H6- 
ritier,  at  the  close  of  the  I5th  century,  Podocarpus  had  al- 
ready been  distinguished  from  the  pines — by  a  seafaring 
man,  too. 

31)0  (p.  85.) — Charles  Darwin,  Journal  of  the  Voyages  of 
the  Adventure  and  Beagle,  1839,  p.  271. 

an  (p.  85.)  —  Goppert  describes  other  three  Cycadeae 
'species  of  Cicaditeie  and  Pterophyllum)  from  the  lignitic 
clay-shists  of  Altsattel  and  Commotau  in  Bohemia,  perhaps 
'rom  the  Eocene  period  (Goppert,  in  the  work  quoted  in 
Note  90). 

302  (p.  85.)— Buckland,  Geology,  p.  509. 

303  (p.  85.)— Leopold  von  Buch,'in  Abhandl.  der  Akad.  der 
Wiss.  zu  Berlin  aus  den  J.  1814—1815,  S.  1(51,  and  in  Pog- 
^endorff's  Annalen,  Bd.  ii.  S.  575 ;  Elie  de  Beaumont,  in 
Annales  des  Sciences  nat.  t.  xix.  p.  60. 

304  (p.  86.) — Vide  Elie  de  Beaumont,  Descr.  g^ol.  de  la 
France,  t.  i.  p.  65  ;  Beudant,  G6ologie,  1844,  p.  209. 

305  (p.  87.)— Transactions  of  the  Cambridge  Philosophi- 
cal Society,  vol.  vi.  pt.  2, 1837,  p.  297.  According  to  others, 
as  100  :  284. 

30ti  (p.  87.) — In  the  middle  ages  the  prevalent  opinion 
MIS  that  the  sea  covered  but  one  seventh  of  the  surface  of 
.ne  globe,  an  opinion  which  Cardinal  d'Ailly  (Imago  Mun- 
di,  cap.  8)  founded  on  the  Apocryphal  4th  Book  of  Ezra. 
Columbus,  who  always  derived'  much  of  his  cosmological 
Jinowledge  from  the  Cardinal's  work,  was  much  interested 
in  upholding  this  idea  of  the  smallness  of  the  sea,  to  which 
the  misunderstood  expression  of  "  the  ocean  stream"  con- 
tributed not  a  little.  Vide  Humboldt,  Examen  critique  de 
I'Hist.  de  la  Geographic,  t.  i.  p.  186. 

307  (p.  87.) — Agathemeros,  in  Hudson,  Geographi  mi- 
nbres,  t.  ii.  p.  4.  Vide  Humboldt,  Asie  centr.  t.  i.  p.  120, 
125. 

308  (p.  87.)— Strabo,  lib.  i.  p.  65,  Casaub,  Vide  Hum- 
boldt, Examen  crit.  t.  i.  p.  152. 

309  (p.  87.) — On  the  mean  latitude  of  the  Northern  Asiatic 
shores,  and  the  true  name  of  Cape  Tairaura  (Cape  Siewero 
— Wostotschnoi),  and  Cape  North-East  (Schalagskoi  Mys"), 
vide  Humboldt,  Asie  centrale,  t.  iii.  p.  35  and  37. 

310  (p.  88.)— lb.  t.  i.  p.  198—200.  The  southern  point  of 
America  and  the  Archipelago,  which  we  call  Terra  del  Fu- 
ego,  lies  in  the  meridian  of  the  north-western  part  of  Baf- 
fin's Bay,  and  of  the  great  uncircumscribed  polar  land, 
which  perhaps  belongs  to  West  Greenland. 

311  (p.  88.)— Strabo,  lib.  ii.  p.  92  and  108,  Casaub. 

312  (p.  88.)— Humboldt,  Asie  centrale,  t.  iii.  p.  25.  I  had 
already,  at  an  early  period  of  my  work,  De  distributione 
geographica  plantarum  secundum  coeli  temperiem  et  altitu- 
dinem  montium,  directed  attention  to  the  important  influ- 
ence of  compact  or  divided  continents  on  climate  and  hu- 
man civilization:  "  Regiones  vel  per  sinus  lunatos  in  longa 
cornua  porrectae,  angulosis  littorum  recessibus  quasi  mem- 
bratim  disccrptae,  vel  spatia  patentia  in  immensum,  quo- 
rum littora  nuUis  incisa  angulis  ambit  sine  anfractu  Ocea- 
nus"  (p.  81  and  182).  On  the  relations  of  the  extent  of 
coast  to  the  area  of  a  continent  (at  the  same  time  as  a 
measure  of  the  accessibility  of  the  interior),  vide  the  Inqui- 
ries in  Berghaus,  Annalen  der  Erdkunde,  Bd.  xii.  1835,  S. 
490,  and  Physikal.  Atlas,  1839,  No.  iii.  S.  69. 

313  (p.  88.)— Strabo,  lib.  ii.  p.  92  and  198,  Casaub. 

314  (p.  88.)— Of  Africa,  Pliny  says  (v.  1.)—"  Nee  alia  pars 
terrarum  pauciores  recipit  sinus."  The  small  Indian  pe- 
ninsula this  side  the  Ganges,  in  its  triangular  outline,  pre- 
sents another  analogous  form.  In  Ancient  Greece  there 
prevailed  an  opinion  of  the  regular  configuration  of  the  dry 
land.  There  were  four  gulphs  or  bays,  among  which  the 
Persian  was  placed  in  opposition  to  the  Hyrcanian  (i.  e.  the 
Caspian  Sea)  (Arrian,  vii.  16  ;  Plut.  in  vita  Alexandri,cap, 
44 ;  Dionys.  Perieg.  v.  48  und  630,  pag.  11  und  38,  Bernh.) 
These  four  bays  and  the  isthmuses  of  the  land,  according 
to  the  optical  fancies  of  Agesianax,  were  reflected  in  the 


moon  (Plut.  de  Facie  in  Oifce  Lunae,  p.  921,  19).  On  thfl 
terra  quadrifida,  or  four  divisions  of  the  dry  land,  cf  which 
two  lay  north,  two  south  of  the  equator, "wtde  Macrobius, 
Comm.  in  Somnium  Scipionis,  ii.  9.  1  have  submitted  this 
portion  of  the  geography  of  the  ancients,  on  which  great 
confusion  prevails,  to  a  new  and  careful  examinatitm,  in 
my  Examen  crit.  de  I'Hist.  de  la  G6ogr.  t.  i.  p.  119,  145^ 
180—185,  as  also  in  Asie  centr.  t.  ii.  p.  172—178. 

315  (p.  88.)  —  Flcurieu,  in  Voyage  de  Merchand  autour 
du  Monde,  t.  iv.  p.  38—42. 

3lt;  (p.  88.)— Humboldt,  in  the  Journal  de  Physique,  t. 
liii.  1799,  p.  33,  and  Rel.  hist.  t.  ii.  p.  19,  t.  iii.  p.  189  and 
198. 

317  (p.  88.)  —  Humboldt,  in  PoggendorfTs  Annalen  der 
Physik,  Bd.  xl.  S.  171.  On  the  remarkable  Fiord  forma- 
tion of  the  south-east  end  of  America,  vide  Darwin's  Jour- 
nal (Narrative  of  the  Voyages  of  the  Adventure  and  Beagle, 
vol.  iii.)  1839,  p.  266.  The  parallelism  of  the  two  mount- 
ain chains  is  maintained  from  5°  North  to  5°  South  latitude. 
The  change  in  the  direction  of  the  coast  at  Arica  appears 
to  be  a  consequence  of  the  altered  course  of  the  chasm  upon 
or  through  which  the  Andes  have  arisen. 

318  (p.  89.) — De  la  Beche,  Sections  and  Views  illustrative 
of  Geological  Phenomena,  1830,  Tab.  40  ;  Charles  Babbage, 
Observations  on  the  Temple  of  Serapis  at  Pozzuoli,  near 
Naples,  and  on  certain  causes  which  may  produce  Geologi- 
cal Cycles  of  great  extent,  1834.  A  bed  of  sandstone,  fivo 
English  miles  thick,  heated  to  100°  Fahr.,  would  rise  on 
its  surface  about  25  feet.  Clay  strata  heated,  on  the  con- 
trary, would  occasion  a  contraction  or  sinking  of  the  ground. 
See  the  calculation  for  the  secular  rise  of  Sweden,  on  the 
presumption  of  a  rise  by  so  small  a  quantity  as  3°  Reaum., 
in  a  stratum  140,000  feet  thick,  heated  to  the  melting  point, 
in  Bischoff,  Wftrmelehre  des  Innern  unseres  Erdkorpers, 
S.  303. 

319  (p.  69.) — The  presumption  of  the  stability — which  has 
hitherto  been  so  implicit — of  the  point  of  gravity,  has  at  all 
events  been  shaken  to  a  certain  extent  by  the  gradual  rise 
of  large  portions  of  the  earth's  surface.  Vide  Bessel  Uber 
Maass  und  Gewicht,  in  Schumacher's  Jahrbuch  fiir  1840, 
S.  134. 

320  (p.  89.)  -  Th.  ii.  (1810),  S.  389.  Vide  Hallstrom,  in 
Kongl.  Vetenskaps-Academiens  Ilandlingar  (Stockh.),  1823, 
p.  39  ;  Lyell,  in  the  Philos.  Trans,  for  1835,  p.  1  ;  Blom 
(Amtmann  in  Budskerud),  Stat.  Beschr.  von  Norwegcn, 
1843,  S.  89—116.  If  not  before  Von  Buch's  travels  through 
Scandinavia,  still  before  the  publication  of  the  account  of 
them,  Playfair,  in  his  Illustrations  of  the  Huttonian  Theo- 
ry, ()  393,  as  well  as  Keilhau  (Om  Landjordens  Stigning  in 
Norge  in  dem  Nyt  Magazin  for  Naturvidenskaherene),  «ud 
even  before  Playfair,  the  Dane  Jessen,  had  expressed  au 
opinion  that  it  was  not  the  sea  which  fell  in  level,  but  the 
firm  land  of  Sweden  whijch  rose  :  these  ideas  remained 
wholly  unknown  to  our  great  geologist,  and  exerted  no  in- 
fluence on  the  progress  of  physical  geography.  Jessen,  in 
his  work,  Kougeriget  Norge  fremstillet  efter  nets  naturiige 
og  borgerlige  Tilstand,  Kjcibenh.  1763,  sought  to  explain 
the  changes  in  the  relative  levels  of  the  land  and  soa,  upon 
the  old  notions  of  Celsius,  Kalm,  and  Dahn.  He  broache.s 
some  confused  notions  about  the  possibility  of  an  intern:il 
growth  of  rocks,  but  finally  declares  himself  in  favour  of  an 
upliftment  of  the  land  by  earthquakes.  "All  along,"  he 
observes,  "no  such  rising  was  apparent  immediately  after 
the  earthquake  of  Egersund  ;  still,  other  causes  producing 
such  an  effect  may  have  been  brought  into  operation  by  it." 

321  (p.  89.) — Berzelius,  Jahresbericht  iiberdie  Fortschritie 
der  physischen  Wiss.  No.  18,  S.  686.  The  island  Saltholm, 
over  against  Copenhagen,  and  Bornholm,  however,  rise  but 
very  little — Bornholm  scarcely  1  foot  in  a  century ;  vidn 
Forchhammer,  in  Philos.  Magazine.  3d  Series,  vol.  ii.  p.  3(.',). 

322  (p.  89.)— KeilhEU,  in  Nyt  Mag.  for  Naturvid.  IS.%, 
Bd.  i.  p.  105—254,  Bd.  ii.  p.  57  ;  Bravais,  sur  les  ligms 
d'ancien  niveau  de  la  Mer,  1843,  p.  15— 40.  See  also  Dar- 
win on  the  Parallel  Roads  of  Glen-Roy  and  Lochaber,  in 
the  Philos.  Transactions  for  1839,  p.  60. 

323  (p.  89.)— Humboldt,  Asie  centrale,  t.  ii.  p.  319—321, 
t.  iii.  p.  549 — 554.  The  depression  of  the  Dead  Sea  has 
been  again  and  again  determined  by  the  barometrical  meas- 
urements of  Count  Bertou,  the  more  careful  ones  of  Rus- 
segger,  and  the  trigonometrical  survey  of  Lieut.  Symoiul, 
of  the  Royal  Navy,  who  specifies  1506  feet  as  the  difference 
of  level  between  the  surface  of  the  Dead  Sea  and  the  high- 
est houses  in  Jaffa.  Mr.  Alderson,  who  communicated  this 
result  to  the  Geographical  Society  of  London,  in  a  letter, 
of  the  contents  of  which  I  was  informed  by  my  friend  Cap- 
tain Washington,  Mr.  Alderson  then  imagined  (Nov.  28. 
1841)  that  the  Dead  Sea  layabout  1314  feet  under  the  level 
of  the  Mediterranean.  In  another  and  later  communica- 
tion from  Lieut.  Symond  (Jameson's  Edinburgh  New  Phil- 
osophical Journal,  vol.  xxxiv.  1843,  p.  178),  as  a  final  r*>. 
suit,  two  trigonometrical  operati-ons  are  detailed,  which 
agree  remarkably  with  each  other,  and  assign  1231  feet 
(Paris  measure)  as  the  depression  of  the  level  of  the  Dead 
Sea  below  that  of  the  Mediterranean. 


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